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Chemistry An Atoms First Approach

Steven S. Zumdahl, Susan A. Zumdahl

Chapter 13

Chemical Equilibrium - all with Video Answers

Educators

MB

Chapter Questions

05:07

Problem 1

Consider two beakers of pure water at different temperatures. How do their $\mathrm{pH}$ values compare? Which is more acidic? More basic? Explain.

MB
Marisa Bellino
Numerade Educator
09:48

Problem 2

Differentiate between the terms strength and concentration as they apply to acids and bases. When is HCl strong? Weak? Concentrated? Dilute? Answer the same questions for ammonia. Is the conjugate base of a weak acid a strong base?

MB
Marisa Bellino
Numerade Educator
03:45

Problem 3

Sketch two graphs: (a) percent dissociation for weak acid HA versus the initial concentration of $\mathrm{HA}\left([\mathrm{HA}]_{0}\right)$ and (b) $\mathrm{H}^{+}$ concentration versus [HA]o. Explain both.

MB
Marisa Bellino
Numerade Educator
02:23

Problem 4

Consider a solution prepared by mixing a weak acid HA and HCl. What are the major species? Explain what is occurring in solution. How would you calculate the pH? What if you added NaA to this solution? Then added NaOH?

Eric Ferrara
Eric Ferrara
Numerade Educator
03:21

Problem 5

Explain why salts can be acidic, basic, or neutral, and show examples. Do this without specific numbers.

Anatole Borisov
Anatole Borisov
Numerade Educator
05:49

Problem 6

Consider two separate aqueous solutions: one of a weak acid HA and one of HCl. Assuming you started with 10 molecules of each:
a. Draw a picture of what each solution looks like at equilibrium.
b. What are the major species in each beaker?
c. From your pictures, calculate the $K_{\mathrm{a}}$ values of each acid.
d. Order the following from the strongest to the weakest base: $\mathrm{H}_{2} \mathrm{O}, \mathrm{A}^{-}, \mathrm{Cl}^{-} .$ Explain your order.

Eric Ferrara
Eric Ferrara
Numerade Educator
01:13

Problem 7

You are asked to calculate the $\mathrm{H}^{+}$ concentration in a solution of $\mathrm{NaOH}(a q) .$ Because sodium hydroxide is a base, can we say there is no $\mathrm{H}^{+}$, since having $\mathrm{H}^{+}$ would imply that the solution is acidic?

Anatole Borisov
Anatole Borisov
Numerade Educator
04:46

Problem 8

Consider a solution prepared by mixing a weak acid HA, HCl, and NaA. Which of the following statements best describes what happens?
a. The $\mathrm{H}^{+}$ from the HCl reacts completely with the $\mathrm{A}^{-}$ from the NaA. Then the HA dissociates somewhat.
b. The $\mathrm{H}^{+}$ from the HCl reacts somewhat with the $\mathrm{A}^{-}$ from the NaA to make HA, while the HA is dissociating. Eventually you have equal amounts of everything.
c. The $\mathrm{H}^{+}$ from the HCl reacts somewhat with the $\mathrm{A}^{-}$ from the NaA to make HA while the HA is dissociating. Eventually all the reactions have equal rates.
d. The $\mathrm{H}^{+}$ from the HCl reacts completely with the $\mathrm{A}^{-}$ from the NaA. Then the HA dissociates somewhat until "too much" $\mathrm{H}^{+}$ and $\mathrm{A}^{-}$ are formed, so the $\mathrm{H}^{+}$ and $\mathrm{A}^{-}$ react to form HA, and so on. Eventually equilibrium is reached. Justify your choice, and for choices you did not pick, explain what is wrong with them.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:20

Problem 9

Consider a solution formed by mixing $100.0 \mathrm{mL}$ of $0.10 \mathrm{M}$ HA $\left(K_{\mathrm{a}}=1.0 \times 10^{-6}\right), 100.00 \mathrm{mL}$ of $0.10 M \mathrm{NaA},$ and
$100.0 \mathrm{mL}$ of $0.10 \mathrm{M}$ HCl. In calculating the $\mathrm{pH}$ for the final solution, you would make some assumptions about the order in which various reactions occur to simplify the calculations. State these assumptions. Does it matter whether the reactions actually occur in the assumed order? Explain.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:37

Problem 10

A certain sodium compound is dissolved in water to liberate Na^{+ ions and a certain negative ion. What evidence would you } look for to determine whether the anion is behaving as an acid or a base? How could you tell whether the anion is a strong base? Explain how the anion could behave simultaneously as an acid and a base.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:22

Problem 11

Acids and bases can be thought of as chemical opposites (acids are proton donors, and bases are proton acceptors). Therefore, one might think that $K_{\mathrm{a}}=1 / K_{\mathrm{b}} .$ Why isn't this the case? What is the relationship between $K_{\mathrm{a}}$ and $K_{\mathrm{b}}$ ? Prove it with a derivation.

Anatole Borisov
Anatole Borisov
Numerade Educator
02:38

Problem 12

Consider two solutions of the salts $\mathrm{NaX}(a q)$ and $\mathrm{NaY}(a q)$ at equal concentrations. What would you need to know to determine which solution has the higher pH? Explain how you would decide (perhaps even provide a sample calculation).

Eric Ferrara
Eric Ferrara
Numerade Educator
01:56

Problem 13

What is meant by pH? True or false: A strong acid solution always has a lower $\mathrm{pH}$ than a weak acid solution. Explain.

Anatole Borisov
Anatole Borisov
Numerade Educator
02:42

Problem 14

Why is the $\mathrm{pH}$ of water at $25^{\circ} \mathrm{C}$ equal to $7.00 ?$

Eric Ferrara
Eric Ferrara
Numerade Educator
01:26

Problem 15

Can the $\mathrm{pH}$ of a solution be negative? Explain.

Anatole Borisov
Anatole Borisov
Numerade Educator
03:05

Problem 16

Is the conjugate base of a weak acid a strong base? Explain. Explain why $\mathrm{Cl}^{-}$ does not affect the $\mathrm{pH}$ of an aqueous solution.

Eric Ferrara
Eric Ferrara
Numerade Educator
01:31

Problem 17

Match the following pH values: $1,2,5,6,6.5,8,11,11,$ and 13 with the following chemicals (of equal concentration):
HBr, NaOH, NaF, NaCN, $\mathrm{NH}_{4} \mathrm{F}, \mathrm{CH}_{3} \mathrm{NH}_{3} \mathrm{F}, \mathrm{HF}, \mathrm{HCN},$ and
$\mathrm{NH}_{3} .$ Answer this question without performing calculations.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:37

Problem 18

The salt $\mathrm{BX}$, when dissolved in water, produces an acidic solution. Which of the following could be true? (There may be more than one correct answer.
a. The acid HX is a weak acid.
b. The acid HX is a strong acid.
c. The cation $B^{+}$ is a weak acid.
Explain.

Eric Ferrara
Eric Ferrara
Numerade Educator
03:20

Problem 19

Anions containing hydrogen (for example, $\mathrm{HCO}_{3}^{-}$ and $\mathrm{H}_{2} \mathrm{PO}_{4}^{-}$ ) usually show amphoteric behavior. Write equations illustrating the amphoterism of these two anions.

Ian Kaigh
Ian Kaigh
Numerade Educator
02:26

Problem 20

Which of the following conditions indicate an acidic solution
at $25^{\circ} \mathrm{C} ?$
a. $\mathrm{pH}=3.04$
b. $\left[\mathrm{H}^{+}\right]>1.0 \times 10^{-7} M$
c. $\mathrm{pOH}=4.51$
d. $\left[\mathrm{OH}^{-}\right]=3.21 \times 10^{-12} \mathrm{M}$

Eric Ferrara
Eric Ferrara
Numerade Educator
01:27

Problem 21

Which of the following conditions indicate a basic solution at $25^{\circ} \mathrm{C} ?$
a. $\mathrm{pOH}=11.21$
b. $p H=9.42$
c. $\left[O H^{-}\right]>\left[H^{+}\right]$
d. $\left[\mathrm{OH}^{-}\right]>1.0 \times 10^{-7} M$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:23

Problem 22

Why is $\mathrm{H}_{3} \mathrm{O}^{+}$ the strongest acid and $\mathrm{OH}^{-}$ the strongest base that can exist in significant amounts in aqueous solutions?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:05

Problem 23

How many significant figures are there in the following numbers: $10.78,6.78,0.78 ?$ If these were $\mathrm{pH}$ values, to how many significant figures can you express the $\left[\mathrm{H}^{+}\right] ?$ Explain any discrepancies between your answers to the two questions.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:31

Problem 24

In terms of orbitals and electron arrangements, what must be present for a molecule or an ion to act as a Lewis acid? What must be present for a molecule or an ion to act as a Lewis base?

Eric Ferrara
Eric Ferrara
Numerade Educator
02:57

Problem 25

Consider the autoionization of liquid ammonia:
Label each of the species in the equation as an acid or a base and explain your answer.

Ian Kaigh
Ian Kaigh
Numerade Educator
02:07

Problem 26

The following are representations of acid-base reactions:
a. Label each of the species in both equations as an acid or a base and explain your answers.
b. For those species that are acids, which labels apply: Arrhenius acid, Brönsted-Lowry acid, Lewis acid? What about the bases?

Ronald Prasad
Ronald Prasad
Numerade Educator
08:07

Problem 27

Give three example solutions that fit each of the following descriptions.
a. a strong electrolyte solution that is very acidic
b. a strong electrolyte solution that is slightly acidic
c. a strong electrolyte solution that is very basic
d. a strong electrolyte solution that is slightly basic
e. a strong electrolyte solution that is neutral

Ian Kaigh
Ian Kaigh
Numerade Educator
02:15

Problem 28

Derive an expression for the relationship between $\mathrm{p} K_{\mathrm{a}}$ and $\mathrm{p} K_{\mathrm{b}}$ for a conjugate acid-base pair. $(p K=-\log K .)$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:41

Problem 29

Consider the following statements. Write out an example reaction and $K$ expression that is associated with each statement.
a. The autoionization of water.
b. An acid reacts with water to produce the conjugate base of the acid and the hydroniumion.
c. A base reacts with water to produce the conjugate acid of the base and the hydroxide ion.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:45

Problem 30

Which of the following statements is(are) true? Correct the false statements.
a. When a base is dissolved in water, the lowest possible pH of the solution is $7.0 .$
b. When an acid is dissolved in water, the lowest possible
$\mathrm{pH}$ is 0
c. A strong acid solution will have a lower $p H$ than a weak acid solution.
d. $A 0.0010-M B a(O H)_{2}$ solution has a pOH that is twice the pOH value of a 0.0010-M KOH solution.

Ronald Prasad
Ronald Prasad
Numerade Educator
07:46

Problem 31

Consider the following mathematical expressions.
a. $\left[\mathrm{H}^{+}\right]=[\mathrm{HA}]_{0}$
b. $\left[\mathrm{H}^{+}\right]=\left(K_{\mathrm{a}} \times[\mathrm{HA}]_{0}\right)^{1 / 2}$
c. $\left[\mathrm{OH}^{-}\right]=2[\mathrm{B}]_{0}$
d. $\left[\mathrm{OH}^{-}\right]=\left(K_{\mathrm{b}} \times[\mathrm{B}]_{0}\right)^{1 / 2}$
For each expression, give three solutions where the mathematical expression would give a good approximation for the $\left[\mathrm{H}^{+}\right]$ or $\left[\mathrm{OH}^{-}\right] .[\mathrm{HA}]_{0}$ and $[\mathrm{B}]_{0}$ represent initial concentrations of an acid
or a base.

Ian Kaigh
Ian Kaigh
Numerade Educator
03:01

Problem 32

Consider a $0.10-M \mathrm{H}_{2} \mathrm{CO}_{3}$ solution and a $0.10-M \mathrm{H}_{2} \mathrm{SO}_{4}$ solution. Without doing any detailed calculations, choose one of the following statements that best describes the $\left[\mathrm{H}^{+}\right]$ of each solution and explain your answer.
a. The $\left[\mathrm{H}^{+}\right]$ is less than $0.10 \mathrm{M}$.
b. The $\left[\mathrm{H}^{+}\right]$ is $0.10 \mathrm{M}$
c. The $\left[\mathrm{H}^{+}\right]$ is between $0.10 \mathrm{M}$ and $0.20 \mathrm{M}$
d. The $\left[\mathrm{H}^{+}\right]$ is $0.20 \mathrm{M}$

Eric Ferrara
Eric Ferrara
Numerade Educator
02:40

Problem 33

Of the hydrogen halides, only HF is a weak acid. Give a possible explanation.

Ian Kaigh
Ian Kaigh
Numerade Educator
01:04

Problem 34

Explain why the following are done, both of which are related to acid-base chemistry.
a. Power plants burning coal with high sulfur content use scrubbers to help eliminate sulfur emissions.
b. A gardener mixes lime (CaO) into the soil of his garden.

Eric Ferrara
Eric Ferrara
Numerade Educator
02:44

Problem 35

Write balanced equations that describe the following reactions.
a. the dissociation of perchloric acid in water
b. the dissociation of propanoic acid $\left(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CO}_{2} \mathrm{H}\right)$ in water
c. the dissociation of ammonium ion in water

Ian Kaigh
Ian Kaigh
Numerade Educator
02:01

Problem 36

Write the dissociation reaction and the corresponding $K_{\mathrm{a}}$ equilibrium expression for each of the following acids in water.
a. HCN
b. $\mathrm{HOC}_{6} \mathrm{H}_{5}$
c. $C_{6} H_{5} N H_{3}+$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:14

Problem 37

For each of the following aqueous reactions, identify the acid, the base, the conjugate base, and the conjugate acid.
a. $\mathrm{H}_{2} \mathrm{O}+\mathrm{H}_{2} \mathrm{CO}_{3} \rightleftharpoons \mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{HCO}_{3}^{-}$
b. $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NH}^{+}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}+\mathrm{H}_{3} \mathrm{O}^{+}$
c. $\mathrm{HCO}_{3}^{-}+\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NH}^{+} \rightleftharpoons \mathrm{H}_{2} \mathrm{CO}_{3}+\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}$

Ian Kaigh
Ian Kaigh
Numerade Educator
02:43

Problem 38

For each of the following aqueous reactions, identify the acid, the base, the conjugate base, and the conjugate acid.
a. $\mathrm{Al}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{Al}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5}(\mathrm{OH})^{2+}$
b. $\mathrm{H}_{2} \mathrm{O}+\mathrm{HONH}_{3}^{+} \rightleftharpoons \mathrm{HONH}_{2}+\mathrm{H}_{3} \mathrm{O}^{+}$
c. HOCl $+\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2} \rightleftharpoons \mathrm{OCl}^{-}+\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3}^{+}$

Eric Ferrara
Eric Ferrara
Numerade Educator
01:38

Problem 39

Classify each of the following as a strong acid or a weak acid.

Ian Kaigh
Ian Kaigh
Numerade Educator
02:22

Problem 40

Consider the following illustrations:
Which beaker best illustrates what happens when the following acids are dissolved in water?
a. $\mathrm{HNO}_{2}$
d. HF
b. $\mathrm{HNO}_{3}$
e. $\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$
c. HCl

Ronald Prasad
Ronald Prasad
Numerade Educator
00:23

Problem 41

Use Table $13-2$ to order the following from the strongest to the weakest acid.
$$\mathrm{HClO}_{2}, \quad \mathrm{H}_{2} \mathrm{O}, \quad \mathrm{NH}_{4}^{+}, \quad \mathrm{HClO}_{4}$$

Ronald Prasad
Ronald Prasad
Numerade Educator
00:23

Problem 42

Use Table $13-2$ to order the following from the strongest to the weakest base.
$$\mathrm{ClO}_{2}^{-}, \quad \mathrm{H}_{2} \mathrm{O}, \quad \mathrm{NH}_{3}, \quad \mathrm{ClO}_{4}^{-}$$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:34

Problem 43

You may need Table $13-2$ to answer the following questions.
a. Which is the stronger acid, HCl or $\mathrm{H}_{2} \mathrm{O} ?$
b. Which is the stronger acid, $\mathrm{H}_{2} \mathrm{O}$ or $\mathrm{HNO}_{2} ?$
c. Which is the stronger acid, HCN or HOC $_{6} \mathrm{H}_{5}$ ?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:38

Problem 44

You may need Table $13-2$ to answer the following questions.
a. Which is the stronger base, $\mathrm{Cl}^{-}$ or $\mathrm{H}_{2} \mathrm{O} ?$
b. Which is the stronger base, $\mathrm{H}_{2} \mathrm{O}$ or $\mathrm{NO}_{2}^{-} ?$
c. Which is the stronger base, $\mathrm{CN}^{-}$ or $\mathrm{OC}_{6} \mathrm{H}_{5}^{-} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:36

Problem 45

Calculate the $\left[\mathrm{OH}^{-}\right]$ of each of the following solutions at $25^{\circ} \mathrm{C} .$ Identify each solution as neutral, acidic, or basic.
a. $\left[\mathrm{H}^{+}\right]=1.0 \times 10^{-7} \mathrm{M}$ c. $\left[\mathrm{H}^{+}\right]=12 \mathrm{M}$
b. $\left[\mathrm{H}^{+}\right]=8.3 \times 10^{-16} \mathrm{M}$ d. $\left[\mathrm{H}^{+}\right]=5.4 \times 10^{-5} \mathrm{M}$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:43

Problem 46

Calculate the $\left[\mathrm{H}^{+}\right]$ of each of the following solutions at $25^{\circ} \mathrm{C}$ Identify each solution as neutral, acidic, or basic.
a. $\left[\mathrm{OH}^{-}\right]=1.5 \mathrm{M}$
b. $\left[\mathrm{OH}^{-}\right]=3.6 \times 10^{-15} \mathrm{M}$
c. $\left[\mathrm{OH}^{-}\right]=1.0 \times 10^{-7} \mathrm{M}$
d. $\left[\mathrm{OH}^{-}\right]=7.3 \times 10^{-4} \mathrm{M}$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:47

Problem 47

Values of $K_{\mathrm{w}}$ as a function of temperature are as follows:
a. Is the autoionization of water exothermic or endothermic?
b. Calculate $\left[\mathrm{H}^{+}\right]$ and $\left[\mathrm{OH}^{-}\right]$ in a neutral solution at $50 .^{\circ} \mathrm{C}$

Ian Kaigh
Ian Kaigh
Numerade Educator
02:43

Problem 48

At $40 .^{\circ} \mathrm{C}$ the value of $K_{\mathrm{w}}$ is $2.92 \times 10^{-14}$
a. Calculate the $\left[\mathrm{H}^{+}\right]$ and $\left[\mathrm{OH}^{-}\right]$ in pure water at $40^{\circ} \mathrm{C}$
b. What is the pH of pure water at $40 .^{\circ} \mathrm{C} ?$
c. If the hydroxide ion concentration in a solution is $0.10 M$ what is the $\mathrm{pH}$ at $40 .^{\circ} \mathrm{C} ?$

Eric Ferrara
Eric Ferrara
Numerade Educator
03:59

Problem 49

Calculate the $\mathrm{pH}$ and $\mathrm{pOH}$ of the solutions in Exercises 45 and 46

Ronald Prasad
Ronald Prasad
Numerade Educator
06:19

Problem 50

Calculate $\left[\mathrm{H}^{+}\right]$ and $\left[\mathrm{OH}^{-}\right]$ for each solution at $25^{\circ} \mathrm{C}$. Identify each solution as neutral, acidic, or basic.
a. $\mathrm{pH}=7.40$ (the normal $\mathrm{pH}$ of blood)
b. $\mathrm{pH}=15.3$
c. $\mathrm{pH}=-1.0$
d. $p H=3.20$
e. $\mathrm{pOH}=5.0$
f. $p O H=9.60$

Ronald Prasad
Ronald Prasad
Numerade Educator
05:18

Problem 51

Fill in the missing information in the following table.

Eric Ferrara
Eric Ferrara
Numerade Educator
05:18

Problem 52

Fill in the missing information in the following table.

Eric Ferrara
Eric Ferrara
Numerade Educator
01:03

Problem 53

The $\mathrm{pH}$ of a sample of gastric juice in a person's stomach is
2.1. Calculate the pOH, $\left[\mathrm{H}^{+}\right],$ and $\left[\mathrm{OH}^{-}\right]$ for this sample. Is gastric juice acidic or basic?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:00

Problem 54

The pOH of a sample of baking soda dissolved in water is 5.74 at $25^{\circ} \mathrm{C}$. Calculate the $\mathrm{pH},\left[\mathrm{H}^{+}\right],$ and $\left[\mathrm{OH}^{-}\right]$ for this sample. Is the solution acidic or basic?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:10

Problem 55

What are the major species present in 0.250 $M$ solutions of each of the following acids? Calculate the $\mathrm{pH}$ of each of these solutions.
a. $\mathrm{HClO}_{4}$
b. HNO_3

Ronald Prasad
Ronald Prasad
Numerade Educator
02:44

Problem 56

A solution is prepared by adding $50.0 \mathrm{mL}$ of $0.050 \mathrm{M}$ HBr to 150.0 mL of 0.10 $M$ HI. Calculate $\left[\mathrm{H}^{+}\right]$ and the pH of this solution. HBr and HI are both considered strong acids.

Eric Ferrara
Eric Ferrara
Numerade Educator
03:02

Problem 57

Calculate the $\mathrm{pH}$ of each of the following solutions of a strong acid in water.
a. $0.10 \mathrm{M} \mathrm{HCl}$
b. 5.0 M HCl
c. $1.0 \times 10^{-11} \mathrm{M} \mathrm{HCl}$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:14

Problem 58

Calculate the $\mathrm{pH}$ of each of the following solutions containing a strong acid in water.
a. $2.0 \times 10^{-2} M \mathrm{HNO}_{3}$
b. $4.0 \mathrm{M} \mathrm{HNO}_{3}$
c. $6.2 \times 10^{-12} \mathrm{M} \mathrm{HNO}_{3}$

Ronald Prasad
Ronald Prasad
Numerade Educator
00:40

Problem 59

Calculate the concentration of an aqueous HI solution that has $\mathrm{pH}=2.50 .$ HI is a strong acid.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:21

Problem 60

Calculate the concentration of an aqueous HBr solution that has $\mathrm{pH}=4.25 .$ HBr is a strong acid.

Ian Kaigh
Ian Kaigh
Numerade Educator
05:05

Problem 61

How would you prepare $1600 \mathrm{mL}$ of a $\mathrm{pH}=1.50$ solution using concentrated (12 $M$ ) HCl?

Ian Kaigh
Ian Kaigh
Numerade Educator
03:29

Problem 62

A solution is prepared by adding 50.0 mL concentrated hydrochloric acid and $20.0 \mathrm{mL}$ concentrated nitric acid to 300 mL water. More water is added until the final volume is 1.00 L. Calculate $\left[\mathrm{H}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and the $\mathrm{pH}$ for this solution. [Hint:
Concentrated HCl is $38 \%$ HCl (by mass) and has a density of
1.19 g/mL; concentrated HNO_ is 70.\% HNO_3 (by mass) and has a density of $1.42 \mathrm{g} / \mathrm{mL} .]$

Ronald Prasad
Ronald Prasad
Numerade Educator
04:53

Problem 63

What are the major species present in 0.250 $M$ solutions of each of the following acids? Calculate the pH of each of these solutions.
a. $\mathrm{HNO}_{2}$
b. $\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}\left(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)$

Ronald Prasad
Ronald Prasad
Numerade Educator
04:33

Problem 64

What are the major species present in 0.250 $M$ solutions of each of the following acids? Calculate the $\mathrm{pH}$ of each of these solutions.
a. $\mathrm{HOC}_{6} \mathrm{H}_{5}$
b. HCN

Ronald Prasad
Ronald Prasad
Numerade Educator
05:41

Problem 65

Calculate the concentration of all species present and the pH of a 0.020-M HF solution.

Anatole Borisov
Anatole Borisov
Numerade Educator
02:21

Problem 66

Calculate the percent dissociation for a $0.22-M$ solution of chlorous acid (HClO_, $K_{\mathrm{a}}=1.2 \times 10^{-2}$ ).

Ronald Prasad
Ronald Prasad
Numerade Educator
06:03

Problem 67

For propanoic acid $\left(\mathrm{HC}_{3} \mathrm{H}_{5} \mathrm{O}_{2}, K_{\mathrm{a}}=1.3 \times 10^{-5}\right),$ determine the concentration of all species present, the $\mathrm{pH}$, and the percent dissociation of a 0.100-M solution.

Anatole Borisov
Anatole Borisov
Numerade Educator
10:18

Problem 68

A solution is prepared by dissolving 0.56 g benzoic acid $\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CO}_{2} \mathrm{H}, K_{\mathrm{a}}=6.4 \times 10^{-5}\right)$ in enough water to make $1.0 \mathrm{L}$ of solution. Calculate $\left[\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CO}_{2} \mathrm{H}\right],\left[\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CO}_{2}^{-}\right],\left[\mathrm{H}^{+}\right],\left[\mathrm{OH}^{-}\right]$
and the pH of this solution.

James Irizarry
James Irizarry
Numerade Educator
05:16

Problem 69

Monochloroacetic acid, $\mathrm{HC}_{2} \mathrm{H}_{2} \mathrm{ClO}_{2}$, is a skin irritant that is used in "chemical peels" intended to remove the top layer of dead skin from the face and ultimately improve the complexion. The value of $K_{\mathrm{a}}$ for monochloroacetic acid is $1.35 \times 10^{-3}$ Calculate the $\mathrm{pH}$ of a $0.10-M$ solution of monochloroacetic acid.

James Irizarry
James Irizarry
Numerade Educator
06:03

Problem 70

A typical aspirin tablet contains 325 mg acetylsalicylic acid $\left(\mathrm{HC}_{9} \mathrm{H}_{7} \mathrm{O}_{4}\right) .$ Calculate the $\mathrm{pH}$ of a solution that is prepared by dissolving two aspirin tablets in enough water to make one cup $(237 \mathrm{mL})$ of solution. Assume the aspirin tablets are pure acetylsalicylic acid, $K_{\mathrm{a}}=3.3 \times 10^{-4}$

Ian Kaigh
Ian Kaigh
Numerade Educator
04:34

Problem 71

Calculate the pH of a solution that contains $1.0 \mathrm{M}$ HF and $1.0 \mathrm{M} \mathrm{HOC}_{6} \mathrm{H}_{5} .$ Also calculate the concentration of $\mathrm{OC}_{6} \mathrm{H}_{5}^{-}$ in this solution at equilibrium.

Ronald Prasad
Ronald Prasad
Numerade Educator
05:12

Problem 72

A solution is made by adding $50.0 \mathrm{mL}$ of $0.200 \mathrm{M}$ acetic acid $\left(K_{\mathrm{a}}=1.8 \times 10^{-5}\right)$ to $50.0 \mathrm{mL}$ of $1.00 \times 10^{-3} \mathrm{M} \mathrm{HCl}$
a. Calculate the $p$ H of the solution.
b. Calculate the acetate ion concentration.

Ronald Prasad
Ronald Prasad
Numerade Educator
08:06

Problem 73

Calculate the percent dissociation of the acid in each of the following solutions.
a. $0.50 M$ acetic acid
b. 0.050 $M$ acetic acid
c. 0.0050 $M$ acetic acid
d. Use Le Châtelier's principle to explain why percent dissociation increases as the concentration of a weak acid decreases.
e. Even though the percent dissociation increases from solutions a to c, the $\left[\mathrm{H}^{+}\right]$ decreases. Explain.

Anatole Borisov
Anatole Borisov
Numerade Educator
06:21

Problem 74

Using the $K_{\mathrm{a}}$ values in Table $13-2,$ calculate the percent dissociation in a 0.20-M solution of each of the following acids.
a. nitric acid (HNO_3)
b. nitrous acid (HNO_2)
c. phenol $\left(\mathrm{HOC}_{6} \mathrm{H}_{5}\right)$
d. How is percent dissociation of an acid related to the $K_{a}$ value for the acid (assuming equal initial concentrations of acids)?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:42

Problem 75

A $0.15-M$ solution of a weak acid is $3.0 \%$ dissociated. Calculate $K_{\mathrm{a}}$

Anatole Borisov
Anatole Borisov
Numerade Educator
02:59

Problem 76

An acid HX is $25 \%$ dissociated in water. If the equilibrium concentration of HX is 0.30 $M,$ calculate the $K_{\mathrm{a}}$ value for HX.

James Irizarry
James Irizarry
Numerade Educator
02:52

Problem 77

Trichloroacetic acid $\left(\mathrm{CCl}_{3} \mathrm{CO}_{2} \mathrm{H}\right)$ is a corrosive acid that is used to precipitate proteins. The $\mathrm{pH}$ of a $0.050-M$ solution of trichloroacetic acid is the same as the pH of a 0.040-M HCIO_ solution. Calculate $K_{\mathrm{a}}$ for trichloroacetic acid.

Ronald Prasad
Ronald Prasad
Numerade Educator
05:13

Problem 78

The pH of a 0.063-M solution of hypobromous acid (HOBr but usually written HBrO) is 4.95. Calculate $K_{\mathrm{a}}$.

James Irizarry
James Irizarry
Numerade Educator
04:30

Problem 79

A solution of formic acid (HCOOH, $K_{\mathrm{a}}=1.8 \times 10^{-4}$ ) has a pH of $2.70 .$ Calculate the initial concentration of formic acid in this solution.

Anatole Borisov
Anatole Borisov
Numerade Educator
02:55

Problem 80

A typical sample of vinegar has a pH of $3.0 .$ Assuming that vinegar is only an aqueous solution of acetic acid $\left(K_{a}=1.8 \times\right.$ $10^{-5}$ ), calculate the concentration of acetic acid in vinegar.

James Irizarry
James Irizarry
Numerade Educator
03:20

Problem 81

One mole of a weak acid HA was dissolved in 2.0 L of solution. After the system had come to equilibrium, the concentration of HA was found to be 0.45 $M .$ Calculate $K_{\mathrm{a}}$ for HA.

Anatole Borisov
Anatole Borisov
Numerade Educator
04:11

Problem 82

You have $100.0 \mathrm{g}$ saccharin, a sugar substitute, and you want to prepare a $\mathrm{pH}=5.75$ solution. What volume of solution can be prepared? For saccharin, $\mathrm{HC}_{7} \mathrm{H}_{4} \mathrm{NSO}_{3}, \mathrm{p} K_{\mathrm{a}}=11.70$
$\left(p K_{a}=-\log K_{a}\right)$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:33

Problem 83

Write the reaction and the corresponding $K_{\mathrm{b}}$ equilibrium expression for each of the following substances acting as bases in water.
a. $\mathrm{NH}_{3}$
b. $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}$

Anatole Borisov
Anatole Borisov
Numerade Educator
02:53

Problem 84

Write the reaction and the corresponding $K_{\mathrm{b}}$ equilibrium expression for each of the following substances acting as bases in water.
a. aniline, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}$
b. dimethylamine, $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}$

James Irizarry
James Irizarry
Numerade Educator
00:26

Problem 85

Use Table $13-3$ to help order the following bases from strongest to weakest.
$$\mathrm{NO}_{3}^{-}, \quad \mathrm{H}_{2} \mathrm{O}, \quad \mathrm{NH}_{3}, \quad \mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}$$

Ronald Prasad
Ronald Prasad
Numerade Educator
00:29

Problem 86

Use Table $13-3$ to help order the following acids from strongest to weakest.
$$\mathrm{HNO}_{3}, \quad \mathrm{H}_{2} \mathrm{O}, \quad \mathrm{NH}_{4}^{+}, \quad \mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NH}^{+}$$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:29

Problem 87

Use Table $13-3$ to help answer the following questions.
a. Which is the stronger base, $\mathrm{ClO}_{4}^{-}$ or $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2} $
b. Which is the stronger base, $\mathrm{H}_{2} \mathrm{O}$ or $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2} ?$
c. Which is the stronger base, OH- or $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2} ?$
d. Which is the stronger base, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}$ or $\mathrm{CH}_{3} \mathrm{NH}_{2} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:42

Problem 88

Use Table $13-3$ to help answer the following questions.
a. Which is the stronger acid, $\mathrm{HClO}_{4}$ or $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3}^{+}?$
b. Which is the stronger acid, $\mathrm{H}_{2} \mathrm{O}$ or $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3}^{+} ?$
c. Which is the stronger acid, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3}^{+}$ or $\mathrm{CH}_{3} \mathrm{NH}_{3}^{+} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:17

Problem 89

Calculate the $\mathrm{pH}$ of the following solutions.
a. $0.10 M \mathrm{NaOH}$
b. $1.0 \times 10^{-10} M \mathrm{NaOH}$
c. $2.0 \mathrm{M} \mathrm{NaOH}$

Anatole Borisov
Anatole Borisov
Numerade Educator
05:03

Problem 90

Calculate $\left[\mathrm{OH}^{-}\right], \mathrm{pOH},$ and $\mathrm{pH}$ for each of the following.
a. $0.00040 M \mathrm{Ca}(\mathrm{OH})_{2}$
b. a solution containing $25 \mathrm{g}$ KOH per liter
c. a solution containing $150.0 \mathrm{g} \mathrm{NaOH}$ per liter

Ronald Prasad
Ronald Prasad
Numerade Educator
02:03

Problem 91

What are the major species present in 0.015 $M$ solutions of each of the following bases?
a. KOH
b. $\mathrm{Ba}(\mathrm{OH})_{2}$
What is $\left[\mathrm{OH}^{-}\right]$ and the $\mathrm{pH}$ of each of these solutions?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:50

Problem 92

What are the major species present in the following mixtures of bases?
a. $0.050 M \mathrm{NaOH}$ and $0.050 \mathrm{M} \mathrm{LiOH}$
b. $0.0010 M \mathrm{Ca}(\mathrm{OH})_{2}$ and $0.020 \mathrm{M} \mathrm{RbOH}$
What is $\left[\mathrm{OH}^{-}\right]$ and the $\mathrm{pH}$ of each of these solutions?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:37

Problem 93

What mass of KOH is necessary to prepare $800.0 \mathrm{mL}$ of a solution having a $\mathrm{pH}=11.56 ?$

Anatole Borisov
Anatole Borisov
Numerade Educator
03:55

Problem 94

Calculate the concentration of an aqueous $\operatorname{Sr}(\mathrm{OH})_{2}$ that has $\mathrm{pH}=10.50$

James Irizarry
James Irizarry
Numerade Educator
03:13

Problem 95

What are the major species present in a 0.150-M $\mathrm{NH}_{3}$ solution? Calculate the $\left[\mathrm{OH}^{-}\right]$ and the $\mathrm{pH}$ of this solution.

Anatole Borisov
Anatole Borisov
Numerade Educator
04:10

Problem 96

For the reaction of hydrazine $\left(\mathrm{N}_{2} \mathrm{H}_{4}\right)$ in water,
$$\mathrm{H}_{2} \mathrm{NNH}_{2}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{H}_{2} \mathrm{NNH}_{3}^{+}(a q)+\mathrm{OH}^{-}(a q)$$
$K_{\mathrm{b}}$ is $3.0 \times 10^{-6} .$ Calculate the concentrations of all species and the $\mathrm{pH}$ of a $2.0-M$ solution of hydrazine in water.

James Irizarry
James Irizarry
Numerade Educator
05:40

Problem 97

Calculate $\left[\mathrm{OH}^{-}\right],\left[\mathrm{H}^{+}\right],$ and the $\mathrm{pH}$ of $0.20 M$ solutions of each of the following amines.
a. triethylamine $\left[\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{3} \mathrm{N}, K_{\mathrm{b}}=4.0 \times 10^{-4}\right]$
b. hydroxylamine (HONH $\left._{2}, K_{\mathrm{b}}=1.1 \times 10^{-8}\right)$

Ronald Prasad
Ronald Prasad
Numerade Educator
05:08

Problem 98

Calculate $\left[\mathrm{OH}^{-}\right],\left[\mathrm{H}^{+}\right],$ and the $\mathrm{pH}$ of $0.40 M$ solutions of each of the following amines (the $K_{\mathrm{b}}$ values are found in Table 13-3).
a. aniline
b. methylamine

Ronald Prasad
Ronald Prasad
Numerade Educator
02:19

Problem 99

Calculate the $\mathrm{pH}$ of a $0.20-M \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}$ solution $\left(K_{\mathrm{b}}=\right.$ $\left.5.6 \times 10^{-4}\right)$

Anatole Borisov
Anatole Borisov
Numerade Educator
06:01

Problem 100

Calculate the $\mathrm{pH}$ of a $0.050-M\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH}$ solution $\left(K_{\mathrm{b}}=\right.$ $\left.1.3 \times 10^{-3}\right)$

James Irizarry
James Irizarry
Numerade Educator
06:31

Problem 101

What is the percent ionization in each of the following solutions?
a. $0.10 M \mathrm{NH}_{3}$
b. $0.010 M \mathrm{NH}_{3}$
c. $0.10 M C H_{3} N H_{2}$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:11

Problem 102

Calculate the percentage of pyridine $\left(\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}\right)$ that forms pyridinium ion, $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NH}^{+},$ in a $0.10-M$ aqueous solution of pyridine $\left(K_{\mathrm{b}}=1.7 \times 10^{-9}\right)$

James Irizarry
James Irizarry
Numerade Educator
03:07

Problem 103

The $\mathrm{pH}$ of a $0.016-M$ aqueous solution of $p$ -toluidine $\left(\mathrm{CH}_{3} \mathrm{C}_{6} \mathrm{H}_{4} \mathrm{NH}_{2}\right)$ is $8.60 .$ Calculate $K_{\mathrm{b}}$.

Anatole Borisov
Anatole Borisov
Numerade Educator
02:38

Problem 104

Calculate the mass of HONH_ required to dissolve in enough water to make $250.0 \mathrm{mL}$ of solution having a pH of $10.00\left(K_{\mathrm{b}}=\right.$ $\left.1.1 \times 10^{-8}\right)$.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:11

Problem 105

Write out the stepwise $K_{\mathrm{a}}$ reactions for the diprotic acid $\mathrm{H}_{2} \mathrm{SO}_{3}$.

Anatole Borisov
Anatole Borisov
Numerade Educator
01:51

Problem 106

Write out the stepwise $K_{\mathrm{a}}$ reactions for citric acid $\left(\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}\right)$ a triprotic acid.

James Irizarry
James Irizarry
Numerade Educator
04:37

Problem 107

A typical vitamin $\mathrm{C}$ tablet (containing pure ascorbic acid, $\left.\mathrm{H}_{2} \mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{6}\right)$ weighs $500 .$ mg. One vitamin $\mathrm{C}$ tablet is dissolved in enough water to make $200.0 \mathrm{mL}$ of solution. Calculate the pH of this solution. Ascorbic acid is a diprotic acid.

Anatole Borisov
Anatole Borisov
Numerade Educator
06:48

Problem 108

Arsenic acid $\left(\mathrm{H}_{3} \mathrm{AsO}_{4}\right)$ is a triprotic acid with $K_{\mathrm{a}_{\mathrm{i}}}=5.5 \times$
$10^{-3}, K_{\mathrm{a}_{2}}=1.7 \times 10^{-7},$ and $K_{\mathrm{a}_{1}}=5.1 \times 10^{-12} .$ Calculate
$\left[\mathrm{H}^{+}\right],\left[\mathrm{OH}^{-}\right],\left[\mathrm{H}_{3} \mathrm{AsO}_{4}\right],\left[\mathrm{H}_{2} \mathrm{AsO}_{4}^{-}\right],\left[\mathrm{HAsO}_{4}^{2-}\right],$ and $\left[\mathrm{AsO}_{4}^{3-}\right]$
in a $0.20-M$ arsenic acid solution.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:35

Problem 109

Calculate the $\mathrm{pH}$ and $\left[\mathrm{S}^{2-}\right]$ in a $0.10-M \mathrm{H}_{2} \mathrm{S}$ solution. Assume $K_{\mathrm{a}_{\mathrm{t}}}=1.0 \times 10^{-7} ; K_{\mathrm{a}_{2}}=1.0 \times 10^{-19}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
13:11

Problem 110

Calculate $\left[\mathrm{CO}_{3}^{2-}\right]$ in a $0.010-M$ solution of $\mathrm{CO}_{2}$ in water (usually written as $\mathrm{H}_{2} \mathrm{CO}_{3}$ ). If all the $\mathrm{CO}_{3}^{2-}$ in this solution comes from the reaction
$$\mathrm{HCO}_{3}^{-}(a q) \rightleftharpoons \mathrm{H}^{+}(a q)+\mathrm{CO}_{3}^{2-}(a q)$$ what percentage of the $\mathrm{H}^{+}$ ions in the solution is a result of the dissociation of $\mathrm{HCO}_{3}^{-}$ ? When acid is added to a solution of sodium hydrogen carbonate (NaHCO_3), vigorous bubbling occurs. How is this reaction related to the existence of carbonic acid $\left(\mathrm{H}_{2} \mathrm{CO}_{3}\right)$ molecules in aqueous solution?

James Irizarry
James Irizarry
Numerade Educator
01:34

Problem 111

Calculate the $\mathrm{pH}$ of a $2.0-M \mathrm{H}_{2} \mathrm{SO}_{4}$ solution.

Anatole Borisov
Anatole Borisov
Numerade Educator
01:34

Problem 112

Calculate the $\mathrm{pH}$ of a $5.0 \times 10^{-3}-M$ solution of $\mathrm{H}_{2} \mathrm{SO}_{4}$.

James Irizarry
James Irizarry
Numerade Educator
00:26

Problem 113

Arrange the following 0.10 $M$ solutions in order of most acidic to most basic.
$\begin{array}{llll} & \text { KOH, } & \text { KNO }_{3}, & \text { KCN, } & \text { NH_Cl, } & \text { HCl }\end{array}$

Ronald Prasad
Ronald Prasad
Numerade Educator
00:36

Problem 114

Arrange the following 0.10 $M$ solutions in order from most acidic to most basic. See Appendix 5 for $K_{\mathrm{a}}$ and $K_{\mathrm{b}}$ values.
$$\mathrm{CaBr}_{2}, \quad \mathrm{KNO}_{2}, \quad \mathrm{HClO}_{4}, \quad \mathrm{HNO}_{2}, \quad \mathrm{HONH}_{3} \mathrm{ClO}_{4}$$

Ronald Prasad
Ronald Prasad
Numerade Educator
00:55

Problem 115

Given that the $K_{\mathrm{a}}$ value for acetic acid is $1.8 \times 10^{-5}$ and the
$K_{\mathrm{a}}$ value for hypochlorous acid is $3.5 \times 10^{-8},$ which is the stronger base, $\mathrm{OCl}^{-}$ or $\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}^{-} ?$

Anatole Borisov
Anatole Borisov
Numerade Educator
03:21

Problem 116

The $K_{\mathrm{b}}$ values for ammonia and methylamine are $1.8 \times 10^{-5}$ and $4.4 \times 10^{-4}$, respectively. Which is the stronger acid, $\mathrm{NH}_{4}^{+}$ or $\mathrm{CH}_{3} \mathrm{NH}_{3}^{+} ?$

James Irizarry
James Irizarry
Numerade Educator
04:50

Problem 117

Determine $\left[\mathrm{OH}^{-}\right],\left[\mathrm{H}^{+}\right],$ and the $\mathrm{pH}$ of each of the following solutions.
a. $1.0 M$ KCl
b. $1.0 M \mathrm{KC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$

Anatole Borisov
Anatole Borisov
Numerade Educator
04:11

Problem 118

Calculate the concentrations of all species present in a $0.25-M$ solution of ethylammonium chloride $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{3} \mathrm{Cl}\right)$.

James Irizarry
James Irizarry
Numerade Educator
05:23

Problem 119

Calculate the $\mathrm{pH}$ of each of the following solutions.
a. $0.10 M C H_{3} N H_{3} C I$
b. 0.050 M NaCN

Ronald Prasad
Ronald Prasad
Numerade Educator
08:08

Problem 120

Calculate the $\mathrm{pH}$ of each of the following solutions.
a. $0.12 M \mathrm{KNO}_{2}$
b. $0.45 M$ NaOCl
c. $0.40 M \mathrm{NH}_{4} \mathrm{ClO}_{4}$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:48

Problem 121

Sodium azide (NaN, ) is sometimes added to water to kill bacteria. Calculate the concentration of all species in a $0.010-M$ solution of $\mathrm{NaN}_{3} .$ The $K_{\mathrm{a}}$ value for hydrazoic acid $\left(\mathrm{HN}_{3}\right)$ is $1.9 \times 10^{-5}$

Ronald Prasad
Ronald Prasad
Numerade Educator
04:42

Problem 122

Papaverine hydrochloride (abbreviated papH $^{+} \mathrm{Cl}^{-} ;$ molar mass $=378.85 \mathrm{g} / \mathrm{mol}$ ) is a drug that belongs to a group of medicines called vasodilators, which cause blood vessels to expand, thereby increasing blood flow. This drug is the conjugate acid of the weak base papaverine (abbreviated pap; $K_{\mathrm{b}}=$ $8.33 \times 10^{-9}$ at $35.0^{\circ} \mathrm{C}$ ). Calculate the $\mathrm{pH}$ of a $30.0-\mathrm{mg} / \mathrm{mL}$
aqueous dose of papH $^{+} \mathrm{Cl}^{-}$ prepared at $35.0^{\circ} \mathrm{C} . K_{\mathrm{w}}$ at $35.0^{\circ} \mathrm{C}$
is $2.1 \times 10^{-14}$.

James Irizarry
James Irizarry
Numerade Educator
04:25

Problem 123

An unknown salt is either $\mathrm{NaCN}, \mathrm{NaC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}, \mathrm{NaF}, \mathrm{NaCl},$ or
NaOCl. When 0.100 mole of the salt is dissolved in 1.00 L of solution, the $\mathrm{pH}$ of the solution is $8.07 .$ What is the identity of the salt?

Anatole Borisov
Anatole Borisov
Numerade Educator
03:20

Problem 124

Consider a solution of an unknown salt having the general formula BHCl, where $B$ is one of the weak bases in Table $13-3$ A $0.10-M$ solution of the unknown salt has a pH of $5.82 .$ What is the actual formula of the salt?

Hailey Tomashek
Hailey Tomashek
Numerade Educator
04:40

Problem 125

A $0.050-M$ solution of the salt NaB has a pH of $9.00 .$ Calculate the pH of a 0.010-M solution of HB.

Anatole Borisov
Anatole Borisov
Numerade Educator
05:14

Problem 126

A $0.20-M$ sodium chlorobenzoate $\left(\mathrm{NaC}_{7} \mathrm{H}_{4} \mathrm{ClO}_{2}\right)$ solution has a pH of $8.65 .$ Calculate the pH of a 0.20- $M$ chlorobenzoic acid $\left(\mathrm{HC}_{7} \mathrm{H}_{4} \mathrm{ClO}_{2}\right)$ solution.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:17

Problem 127

Calculate the $\mathrm{pH}$ of a $0.050-M$ Al(NO_3)a solution. The $K_{\mathrm{a}}$ value for $\mathrm{Al}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+}$ is $1.4 \times 10^{-5}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
05:22

Problem 128

Calculate the $\mathrm{pH}$ of a $0.10-M \mathrm{CoCl}_{3}$ solution. The $K_{\mathrm{a}}$ value for $\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+}$ is $1.0 \times 10^{-5}$

James Irizarry
James Irizarry
Numerade Educator
03:54

Problem 129

Are solutions of the following salts acidic, basic, or neutral? For those that are not neutral, write balanced chemical equations for the reactions causing the solution to be acidic or basic. The relevant $K_{\mathrm{a}}$ and $K_{\mathrm{b}}$ values are found in Tables $13-2$ and $13-3$
a. $\mathrm{NaNO}_{3}$
b. $\mathrm{NaNO}_{2}$
c. $C_{5} H_{5} N H C I O_{4}$
d. $\mathrm{NH}_{4} \mathrm{NO}_{2}$
e. $\mathrm{KOCl}$
f. $\mathrm{NH}_{4} \mathrm{OCl}$

Ronald Prasad
Ronald Prasad
Numerade Educator
07:53

Problem 130

Are solutions of the following salts acidic, basic, or neutral? For those that are not neutral, write balanced equations for the reactions causing the solution to be acidic or basic. The relevant $K_{\mathrm{a}}$ and $K_{\mathrm{b}}$ values are found in Tables $13-2$ and $13-3$
a. $\operatorname{Sr}\left(\mathrm{NO}_{3}\right)_{2}$
b. $\mathrm{NH}_{4} \mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$
c. $\mathrm{CH}_{3} \mathrm{NH}_{3} \mathrm{Cl}$
d. $C_{6} H_{5} N H_{3} C l O_{2}$
e. $\mathrm{NH}_{4} \mathrm{F}$
$\mathbf{f .} \mathrm{CH}_{3} \mathrm{NH}_{3} \mathrm{CN}$

Ronald Prasad
Ronald Prasad
Numerade Educator
05:18

Problem 131

Place the species in each of the following groups in order of increasing acid strength. Explain the order you chose for each group.
a. $\mathrm{HIO}_{3}, \mathrm{HBrO}_{3}$
b. $\mathrm{HNO}_{2}, \mathrm{HNO}_{3}$
c. HOCI, HOI
d. $\mathrm{H}_{3} \mathrm{PO}_{4}, \mathrm{H}_{3} \mathrm{PO}_{3}$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:37

Problem 132

Place the species in each of the following groups in order of increasing base strength. Give your reasoning in each case.
a. $\mathrm{IO}_{3}^{-}, \mathrm{BrO}_{3}^{-}$
b. $\mathrm{NO}_{2}^{-}, \mathrm{NO}_{3}^{-}$
c. $\mathrm{OCl}^{-}, \mathrm{OI}^{-}$

James Irizarry
James Irizarry
Numerade Educator
03:35

Problem 133

Place the species in each of the following groups in order of increasing acid strength.
a. $\mathrm{H}_{2} \mathrm{O}, \mathrm{H}_{2} \mathrm{S}, \mathrm{H}_{2} \mathrm{Se}$ (bond energies: $\mathrm{H}-\mathrm{O}, 467 \mathrm{kJ} / \mathrm{mol}$;
$\mathrm{H}-\mathrm{S}, 363 \mathrm{kJ} / \mathrm{mol} ; \mathrm{H}-\mathrm{Se}, 276 \mathrm{kJ} / \mathrm{mol})$
b. $\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}, \mathrm{FCH}_{2} \mathrm{CO}_{2} \mathrm{H}, \mathrm{F}_{2} \mathrm{CHCO}_{2} \mathrm{H}, \mathrm{F}_{3} \mathrm{CCO}_{2} \mathrm{H}$
c. $\mathrm{NH}_{4}^{+}, \mathrm{HONH}_{3}^{+}$
d. $\mathrm{NH}_{4}^{+}, \mathrm{PH}_{4}^{+}$ (bond energies: $\mathrm{N}-\mathrm{H}, 391 \mathrm{kJ} / \mathrm{mol} ; \mathrm{P}-\mathrm{H}$
$322 \mathrm{kJ} / \mathrm{mol})$
Give reasons for the orders you chose.

Ronald Prasad
Ronald Prasad
Numerade Educator
05:10

Problem 134

Using your results from Exercise $133,$ place the species in each of the following groups in order of increasing base strength.
a. $\mathrm{OH}^{-}, \mathrm{SH}^{-}, \mathrm{SeH}^{-}$
b. $\mathrm{NH}_{3}, \mathrm{PH}_{3}$
c. $\mathrm{NH}_{3}, \mathrm{HONH}_{2}$

James Irizarry
James Irizarry
Numerade Educator
View

Problem 135

Will the following oxides give acidic, basic, or neutral solutions when dissolved in water? Write reactions to justify your answers.
a. $\mathrm{CaO}$
b. $\mathrm{SO}_{2}$
c. $\mathrm{Cl}_{2} \mathrm{O}$

Anatole Borisov
Anatole Borisov
Numerade Educator
02:13

Problem 136

Will the following oxides give acidic, basic, or neutral solutions when dissolved in water? Write reactions to justify your answers.
a. $\mathrm{Li}_{2} \mathrm{O}$
b. $\mathrm{CO}_{2}$
c. SrO

James Irizarry
James Irizarry
Numerade Educator
02:40

Problem 137

Identify the Lewis acid and the Lewis base in each of the following reactions.
a. $\mathrm{B}(\mathrm{OH})_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{B}(\mathrm{OH})_{4}^{-}(a q)+\mathrm{H}^{+}(a q)$
b. $\mathrm{Ag}^{+}(a q)+2 \mathrm{NH}_{3}(a q) \rightleftharpoons \mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}(a q)$
c. $\mathrm{BF}_{3}(g)+\mathrm{F}^{-}(a q) \rightleftharpoons \mathrm{BF}_{4}^{-}(a q)$

Anatole Borisov
Anatole Borisov
Numerade Educator
01:07

Problem 138

Identify the Lewis acid and the Lewis base in each of the following reactions.
a. $\mathrm{Fe}^{3+}(a q)+6 \mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+}(a q)$
b. $\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{CN}^{-}(a q) \rightleftharpoons \mathrm{HCN}(a q)+\mathrm{OH}^{-}(a q)$
c. $\mathrm{HgI}_{2}(s)+2 \mathrm{I}^{-}(a q) \rightleftharpoons \mathrm{HgI}_{4}^{2-}(a q)$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:21

Problem 139

Aluminum hydroxide is an amphoteric substance. It can act as either a Brönsted-Lowry base or a Lewis acid. Write a reaction showing Al(OH) $_{3}$ acting as a base toward $\mathrm{H}^{+}$ and as an acid toward OH $^{-}$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:07

Problem 140

Zinc hydroxide is an amphoteric substance. Write equations that describe $\mathrm{Zn}(\mathrm{OH})_{2}$ acting as a Brönsted-Lowry base toward $\mathrm{H}^{+}$ and as a Lewis acid toward $\mathrm{OH}^{-}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:46

Problem 141

Would you expect $\mathrm{Fe}^{3+}$ or $\mathrm{Fe}^{2+}$ to be the stronger Lewis acid? Explain.

Anatole Borisov
Anatole Borisov
Numerade Educator
02:29

Problem 142

Use the Lewis acid-base model to explain the following reaction.
$$\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{H}_{2}\mathrm{CO}_{3}(a q)$$

James Irizarry
James Irizarry
Numerade Educator
03:32

Problem 143

A 10.0 -mL sample of an HCl solution has a pH of $2.000 .$ What volume of water must be added to change the pH to 4.000?

Anatole Borisov
Anatole Borisov
Numerade Educator
02:19

Problem 144

Which of the following represent conjugate acid-base pairs? For those pairs that are not conjugates, write the correct conjugate acid or base for each species in the pair.
a. $\mathrm{H}_{2} \mathrm{O}, \mathrm{OH}^{-}$
b. $\mathrm{H}_{2} \mathrm{SO}_{4}, \mathrm{SO}_{4}^{2-}$
c. $\mathrm{H}_{3} \mathrm{PO}_{4}, \mathrm{H}_{2} \mathrm{PO}_{4}^{-}$
d. $\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}, \mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}^{-}$

James Irizarry
James Irizarry
Numerade Educator
05:27

Problem 145

A solution is tested for $\mathrm{pH}$ and conductivity as pictured below:
The solution contains one of the following substances: HCl, $\mathrm{NaOH}, \mathrm{NH}_{4} \mathrm{Cl}, \mathrm{HCN}, \mathrm{NH}_{3}, \mathrm{HF},$ or $\mathrm{NaCN} .$ If the solute con-
centration is about $1.0 \mathrm{M},$ what is the identity of the solute?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:36

Problem 146

The pH of human blood is steady at a value of approximately 7.4 owing to the following equilibrium reactions:
$$\mathrm{CO}_{2}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{H}_{2} \mathrm{CO}_{3}(a q) \rightleftharpoons \mathrm{HCO}_{3}^{-}(a q)+\mathrm{H}^{+}(a q)$$
Acids formed during normal cellular respiration react with the $\mathrm{HCO}_{3}^{-}$ to form carbonic acid, which is in equilibrium with $\mathrm{CO}_{2}(a q)$ and $\mathrm{H}_{2} \mathrm{O}(l) .$ During vigorous exercise, a person's $\mathrm{H}_{2} \mathrm{CO}_{3}$ blood levels were $26.3 \mathrm{mM},$ whereas his $\mathrm{CO}_{2}$ levels were $1.63 \mathrm{mM} .$ On resting, the $\mathrm{H}_{2} \mathrm{CO}_{3}$ levels declined to
24.9 $\mathrm{mM}$. What was the $\mathrm{CO}_{2}$ blood level at rest?

James Irizarry
James Irizarry
Numerade Educator
04:14

Problem 147

Hemoglobin (abbreviated Hb) is a protein that is responsible for the transport of oxygen in the blood of mammals. Each hemoglobin molecule contains four iron atoms that are the binding sites for $\mathrm{O}_{2}$ molecules. The oxygen binding is $\mathrm{pH}$ dependent. The relevant equilibrium reaction is
$$\mathrm{HbH}_{4}^{4+}(a q)+4 \mathrm{O}_{2}(g) \rightleftharpoons \mathrm{Hb}\left(\mathrm{O}_{2}\right)_{4}(a q)+4 \mathrm{H}^{+}(a q)$$
Use Le Châtelier's principle to answer the following.
a. What form of hemoglobin, $\mathrm{HbH}_{4}^{4+}$ or $\mathrm{Hb}\left(\mathrm{O}_{2}\right)_{4},$ is favored in the lungs? What form is favored in the cells?
b. When a person hyperventilates, the concentration of $\mathrm{CO}_{2}$ in the blood is decreased. How does this affect the oxygenbinding equilibrium? How does breathing into a paper bag help to counteract this effect? (See Exercise 146.)
c. When a person has suffered a cardiac arrest, injection of a sodium bicarbonate solution is given. Why is this necessary? (Hint: $\mathrm{CO}_{2}$ blood levels increase during cardiac arrest.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:07

Problem 148

A 0.25 -g sample of lime (CaO) is dissolved in enough water to make 1500 mL of solution. Calculate the $p$ H of the solution.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:53

Problem 149

At $25^{\circ} \mathrm{C},$ a saturated solution of benzoic acid $\left(K_{a}=6.4 \times\right.$ $10^{-5}$ ) has a pH of $2.80 .$ Calculate the water solubility of benzoic acid in moles per liter.

Anatole Borisov
Anatole Borisov
Numerade Educator
06:27

Problem 150

Calculate the $\mathrm{pH}$ of an aqueous solution containing $1.0 \times$ $10^{-2} M \mathrm{HCl}, 1.0 \times 10^{-2} \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4},$ and $1.0 \times 10^{-2} \mathrm{M} \mathrm{HCN}$

Ronald Prasad
Ronald Prasad
Numerade Educator
06:07

Problem 151

Acrylic acid $\left(\mathrm{CH}_{2}=\mathrm{CHCO}_{2} \mathrm{H}\right)$ is a precursor for many important plastics. $K_{\mathrm{a}}$ for acrylic acid is $5.6 \times 10^{-5}$
a. Calculate the $\mathrm{pH}$ of a $0.10-M$ solution of acrylic acid.
b. Calculate the percent dissociation of a 0.10-M solution of acrylic acid.
c. Calculate the $\mathrm{pH}$ of a $0.050-M$ solution of sodium acrylate $\left(\mathrm{NaC}_{3} \mathrm{H}_{3} \mathrm{O}_{2}\right)$

Anatole Borisov
Anatole Borisov
Numerade Educator
01:31

Problem 152

Classify each of the following as a strong acid, weak acid, strong base, or weak base in aqueous solution.
a. $\mathrm{HNO}_{2}$
b. $\mathrm{HNO}_{3}$
c. $\mathrm{CH}_{3} \mathrm{NH}_{2}$
d. $\mathrm{NaOH}$
e. $\mathrm{NH}_{3}$
f. HF
g.
h. $\mathrm{Ca}(\mathrm{OH})_{2}$
i. $\mathrm{H}_{2} \mathrm{SO}_{4}$

Sima Sarker
Sima Sarker
Numerade Educator
04:02

Problem 153

The following illustration displays the relative number of species when an acid, HA, is added to water.
a. Is HA a weak or strong acid? How can you tell?
b. Using the relative numbers given in the illustration, determine the value for $K_{\mathrm{a}}$ and the percent dissociation of the acid. Assume the initial acid concentration is 0.20 $M$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:43

Problem 154

Quinine $\left(\mathrm{C}_{20} \mathrm{H}_{24} \mathrm{N}_{2} \mathrm{O}_{2}\right)$ is the most important alkaloid derived from cinchona bark. It is used as an antimalarial drug. For quinine, $\mathrm{p} K_{\mathrm{b}_{1}}=5.1$ and $\mathrm{p} K_{\mathrm{b}_{2}}=9.7\left(\mathrm{p} K_{\mathrm{b}}=-\log K_{\mathrm{b}}\right) .$ Only
1 g quinine will dissolve in $1900.0 \mathrm{mL}$ of solution. Calculate the $\mathrm{pH}$ of a saturated aqueous solution of quinine. Consider only the reaction $\mathrm{Q}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{QH}^{+}+\mathrm{OH}^{-}$ described by
$\mathrm{p} K_{\mathrm{b}_{1}},$ where $\mathrm{Q}=$ quinine.

James Irizarry
James Irizarry
Numerade Educator
03:16

Problem 155

Codeine $\left(\mathrm{C}_{18} \mathrm{H}_{21} \mathrm{NO}_{3}\right)$ is a derivative of morphine that is used as an analgesic, narcotic, or antitussive. It was once commonly used in cough syrups but is now available only by prescription because of its addictive properties. If the $\mathrm{pH}$ of a $1.7 \times 10^{-3}-M$ solution of codeine is $9.59,$ calculate $K_{\mathrm{b}}$

James Irizarry
James Irizarry
Numerade Educator
02:08

Problem 156

A codeine-containing cough syrup lists codeine sulfate as a major ingredient instead of codeine. The Merck Index gives $\mathrm{C}_{36} \mathrm{H}_{44} \mathrm{N}_{2} \mathrm{O}_{10} \mathrm{S}$ as the formula for codeine sulfate. Describe the composition of codeine sulfate. (See Exercise $155 .$ ) Why is codeine sulfate used instead of codeine?

James Irizarry
James Irizarry
Numerade Educator
02:40

Problem 157

The equilibrium constant $K_{\mathrm{a}}$ for the reaction
$$\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons{\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5}}(\mathrm{OH})^{2+}(a q)+\mathrm{H}_{3} \mathrm{O}^{+}(a q)$$
is $6.0 \times 10^{-3}$
a. Calculate the $\mathrm{pH}$ of a $0.10-M$ solution of $\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+}$
b. Will a $1.0-M$ solution of iron(II) nitrate have a higher or lower $\mathrm{pH}$ than a $1.0-M$ solution of iron(III) nitrate? Explain.

Anatole Borisov
Anatole Borisov
Numerade Educator
01:27

Problem 158

Rank the following 0.10 $M$ solutions in order of increasing pH.
a. HI, HF, NaF, NaI
b. $\mathrm{NH}_{4} \mathrm{Br}, \mathrm{HBr}, \mathrm{KBr}, \mathrm{NH}_{3}$
c. $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3} \mathrm{NO}_{3}, \mathrm{NaNO}_{3}, \mathrm{NaOH}, \mathrm{HOC}_{6} \mathrm{H}_{5}, \mathrm{KOC}_{6} \mathrm{H}_{5}$
$\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{HNO}_{3}$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:35

Problem 159

Is an aqueous solution of NaHSO_ acidic, basic, or neutral? What reaction occurs with water? Calculate the pH of a 0.10-M solution of $\mathrm{NaHSO}_{4}$.

Nicholas Mogoi
Nicholas Mogoi
Numerade Educator
04:05

Problem 160

Calculate the value for the equilibrium constant for each of the following aqueous reactions.
a. $\mathrm{NH}_{3}+\mathrm{H}_{3} \mathrm{O}^{+} \rightleftharpoons \mathrm{NH}_{4}^{+}+\mathrm{H}_{2} \mathrm{O}$
b. $\mathrm{NO}_{2}^{-}+\mathrm{H}_{3} \mathrm{O}^{+} \rightleftharpoons \mathrm{HNO}_{2}+\mathrm{H}_{2} \mathrm{O}$
c. $\mathrm{NH}_{4}^{+}+\mathrm{OH}^{-} \rightleftharpoons \mathrm{NH}_{3}+\mathrm{H}_{2} \mathrm{O}$
d. $\mathrm{HNO}_{2}+\mathrm{OH}^{-} \rightleftharpoons \mathrm{H}_{2} \mathrm{O}+\mathrm{NO}_{2}^{-}$

James Irizarry
James Irizarry
Numerade Educator
05:43

Problem 161

Students are often surprised to learn that organic acids, such as acetic acid, contain - OH groups. Actually, all oxyacids contain hydroxyl groups. Sulfuric acid, usually written as $\mathrm{H}_{2} \mathrm{SO}_{4}$ has the structural formula $\mathrm{SO}_{2}(\mathrm{OH})_{2},$ where $\mathrm{S}$ is the central atom. Identify the acids whose structural formulas are shown below. Why do they behave as acids, while NaOH and KOH are bases?
a. $\mathrm{SO}(\mathrm{OH})_{2}$
b. $\mathrm{ClO}_{2}(\mathrm{OH})$
c. $\mathrm{HPO}(\mathrm{OH})_{2}$

Ian Kaigh
Ian Kaigh
Numerade Educator
00:53

Problem 162

For solutions of the same concentration, as acid strength increases, indicate what happens to each of the following (increases, decreases, or doesn't change).
a. $\left[\mathrm{H}^{+}\right]$
b. $\mathrm{pH}$
c. $\left[\mathrm{OH}^{-}\right]$
d. pOH
$\mathbf{e} . K_{\mathrm{a}}$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:01

Problem 163

Complete the table for each of the following solutions:

Anatole Borisov
Anatole Borisov
Numerade Educator
02:49

Problem 164

Consider a $0.60-M$ solution of $\mathrm{HC}_{3} \mathrm{H}_{5} \mathrm{O}_{3},$ lactic acid $\left(K_{\mathrm{a}}=\right.$ $\left.1.4 \times 10^{-4}\right)$
a. Which of the following are major species in the solution?
i. $\mathrm{HC}_{3} \mathrm{H}_{5} \mathrm{O}_{3}$
ii. $\mathrm{C}_{3} \mathrm{H}_{5} \mathrm{O}_{3}^{-}$
iii. $\mathrm{H}^{+}$
iv. $\mathrm{H}_{2} \mathrm{O}$
$\mathbf{v} . \mathrm{OH}^{-}$
b. Complete the following ICE table in terms of $x,$ the amount (mol/L) of lactic acid that dissociates to reach equilibrium.
c. What is the equilibrium concentration for $\mathrm{C}_{3} \mathrm{H}_{5} \mathrm{O}_{3}^{-} ?$
d. Calculate the $p H$ of the solution.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:38

Problem 165

Consider a $0.67-M$ solution of $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}\left(K_{\mathrm{b}}=5.6 \times 10^{-4}\right)$
a. Which of the following are major species in the solution?
i. $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}$
ii. $\mathrm{H}^{+}$
iii. OH $^{-}$
iv. $\mathrm{H}_{2} \mathrm{O}$
v. $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{3}^{+}$
b. Calculate the $p$ H of this solution.

Ronald Prasad
Ronald Prasad
Numerade Educator
00:59

Problem 166

Rank the following 0.10 $M$ solutions in order of increasing pH.
a. $\mathrm{NH}_{3}$
b. KOH
c. $\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$
d. KCl
e. HCl

Ronald Prasad
Ronald Prasad
Numerade Educator
01:27

Problem 167

Consider $0.25 \mathrm{M}$ solutions of the following salts: $\mathrm{NaCl}$, RbOCI, KI, Ba(CIO_{ } _ { 2 } \text { , and } \mathrm { NH } _ { 4 } \mathrm { NO } _ { 3 } \text { . For each salt, indicate } whether the solution is acidic, basic, or neutral.

Ronald Prasad
Ronald Prasad
Numerade Educator
06:36

Problem 168

Calculate the pH of the following solutions:
a. $1.2 \mathrm{M} \mathrm{CaBr}_{2}$
b. $0.84 M C_{6} H_{5} N H_{3} N O_{3}\left(K_{b} \text { for } C_{6} H_{5} N H_{2}=3.8 \times 10^{-10}\right)$
c. $0.57 M \mathrm{KC}_{7} \mathrm{H}_{5} \mathrm{O}_{2}\left(K_{\mathrm{a}} \text { for } \mathrm{HC}_{7} \mathrm{H}_{5} \mathrm{O}_{2}=6.4 \times 10^{-5}\right)$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:40

Problem 169

Consider 0.10 $M$ solutions of the following compounds:
$\mathrm{AlCl}_{3}, \mathrm{NaCN}, \mathrm{KOH}, \mathrm{CsClO}_{4},$ and NaF. Place these solutions
in order of increasing $\mathrm{pH}$.

Sima Sarker
Sima Sarker
Numerade Educator
02:44

Problem 170

The pH of $1.0 \times 10^{-8} M$ hydrochloric acid is not $8.00 .$ The correct $\mathrm{pH}$ can be calculated by considering the relationship between the molarities of the three principal ions in the solution $\left(\mathrm{H}^{+}, \mathrm{Cl}^{-}, \text {and } \mathrm{OH}^{-}\right) .$ These molarities can be calculated from algebraic equations that can be derived from the considerations given below.
a. The solution is electrically neutral.
b. The hydrochloric acid can be assumed to be $100 \%$ ionized.
c. The product of the molarities of the hydronium ions and the hydroxide ions must equal $K_{\mathrm{w}}$ Calculate the $\mathrm{pH}$ of a $1.0 \times 10^{-8}-M$ HCl solution.

James Irizarry
James Irizarry
Numerade Educator
01:43

Problem 171

Calculate the $\mathrm{pH}$ of a $1.0 \times 10^{-7}-M$ solution of $\mathrm{NaOH}$ in water.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:04

Problem 172

Calculate $\left[\mathrm{OH}^{-}\right]$ in a $3.0 \times 10^{-7}-M$ solution of $\mathrm{Ca}(\mathrm{OH})_{2}$

James Irizarry
James Irizarry
Numerade Educator
04:08

Problem 173

Consider $50.0 \mathrm{mL}$ of a solution of weak acid HA $\left(K_{\mathrm{a}}=\right.$ $1.00 \times 10^{-6} \mathrm{J},$ which has a pH of $4.000 .$ What volume of water must be added to make the $\mathrm{pH}=5.000 ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:49

Problem 174

Making use of the assumptions we ordinarily make in calculating the pH of an aqueous solution of a weak acid, calculate the $\mathrm{pH}$ of a $1.0 \times 10^{-6}-M$ solution of hypobromous acid (HBrO, $K_{\mathrm{a}}=2 \times 10^{-9} \mathrm{J} .$ What is wrong with your answer? Why is it wrong? Without trying to solve the problem, explain what has to be included to solve the problem correctly.

Ronald Prasad
Ronald Prasad
Numerade Educator
06:07

Problem 175

Calculate the $\mathrm{pH}$ of a $0.200-M$ solution of $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NHF}$. Hint:
$\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NHF}$ is a salt composed of $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NH}^{+}$ and $\mathrm{F}^{-}$ ions. The
principal equilibrium in this solution is the best acid reacting with the best base; the reaction for the principal equilibrium is
$$\begin{aligned}
\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NH}^{+}(a q)+\mathrm{F}^{-}(a q) & \rightleftharpoons \\
\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}(a q) &+\mathrm{HF}(a q) \quad K=8.2 \times 10^{-3}\end{aligned}$$

Ronald Prasad
Ronald Prasad
Numerade Educator
07:45

Problem 176

Determine the $\mathrm{pH}$ of a $0.50-M$ solution of $\mathrm{NH}_{4} \mathrm{OCl}$. (See Exercise $175 .$ )

James Irizarry
James Irizarry
Numerade Educator
03:37

Problem 177

Calculate $\left[\mathrm{OH}^{-}\right]$ in a solution obtained by adding $0.0100 \mathrm{mol}$ solid NaOH to 1.00 L of $15.0 \mathrm{M} \mathrm{NH}_{3}$.

Anatole Borisov
Anatole Borisov
Numerade Educator
04:27

Problem 178

What mass of $\mathrm{NaOH}(s)$ must be added to $1.0 \mathrm{L}$ of $0.050 \mathrm{M}$ $\mathrm{NH}_{3}$ to ensure that the percent ionization of $\mathrm{NH}_{3}$ is no greater than $0.0010 \% ?$ Assume no volume change on addition of NaOH.

James Irizarry
James Irizarry
Numerade Educator
03:53

Problem 179

Consider $1000 .$ mL of a $1.00 \times 10^{-4}-M$ solution of a certain acid HA that has a $K_{\mathrm{a}}$ value equal to $1.00 \times 10^{-4} .$ How much water was added or removed (by evaporation) so that a solution remains in which $25.0 \%$ of $\mathrm{HA}$ is dissociated at equilibrium? Assume that HA is nonvolatile.

Anatole Borisov
Anatole Borisov
Numerade Educator
06:47

Problem 180

Calculate the mass of sodium hydroxide that must be added to $1.00 \mathrm{L}$ of $1.00-M \mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$ to double the $\mathrm{pH}$ of the solution
(assume that the added NaOH does not change the volume of the solution).

James Irizarry
James Irizarry
Numerade Educator
03:11

Problem 181

Consider the species $\mathrm{PO}_{4}^{3-}, \mathrm{HPO}_{4}^{2-},$ and $\mathrm{H}_{2} \mathrm{PO}_{4}^{-} .$ Each ion
can act as a base in water. Determine the $K_{\mathrm{b}}$ value for each of these species. Which species is the strongest base?

Anatole Borisov
Anatole Borisov
Numerade Educator
09:19

Problem 182

Calculate the $\mathrm{pH}$ of a $0.10-M$ solution of sodium phosphate. (See Exercise 181.)

James Irizarry
James Irizarry
Numerade Educator
06:35

Problem 183

Will 0.10 $M$ solutions of the following salts be acidic, basic, or neutral? See Appendix 5 for $K_{\mathrm{a}}$ values.
a. ammonium bicarbonate
b. sodium dihydrogen phosphate
c. sodium hydrogen phosphate
d. ammonium dihydrogen phosphate
e. ammonium formate

Anatole Borisov
Anatole Borisov
Numerade Educator
05:22

Problem 184

a. The principal equilibrium in a solution of $\mathrm{NaHCO}_{3}$ is
$$\mathrm{HCO}_{3}^{-}(a q)+\mathrm{HCO}_{3}^{-}(a q) \rightleftharpoons \mathrm{H}_{2} \mathrm{CO}_{3}(a q)+\mathrm{CO}_{3}^{2-}(a q)$$
Calculate the value of the equilibrium constant for this reaction.
b. At equilibrium, what is the relationship between $\left[\mathrm{H}_{2} \mathrm{CO}_{3}\right]$ and $\left[\mathrm{CO}_{3}^{2-}\right] ?$
c. Using the equilibrium $$\mathrm{H}_{2} \mathrm{CO}_{3}(a q) \rightleftharpoons 2 \mathrm{H}^{+}(a q)+\mathrm{CO}_{3}^{2-}(a q)$$
derive an expression for the $\mathrm{pH}$ of the solution in terms of
$K_{\mathrm{a}_{\mathrm{j}}}$ and $K_{\mathrm{a}_{\mathrm{z}}}$ using the result from part b.
d. What is the $\mathrm{pH}$ of a solution of $\mathrm{NaHCO}_{3} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
07:53

Problem 185

A $0.100-\mathrm{g}$ sample of the weak acid HA (molar mass $=$ $100.0 \mathrm{g} / \mathrm{mol}$ ) is dissolved in $500.0 \mathrm{g}$ water. The freezing point of the resulting solution is $-0.0056^{\circ} \mathrm{C}$. Calculate the value of
$K_{\mathrm{a}}$ for this acid. Assume molality equals molarity in this solution.

Anatole Borisov
Anatole Borisov
Numerade Educator
10:27

Problem 186

A sample containing 0.0500 mole of $\mathrm{Fe}_{2}\left(\mathrm{SO}_{4}\right)_{3}$ is dissolved in enough water to make 1.00 L of solution. This solution contains hydrated $\mathrm{SO}_{4}^{2-}$ and $\mathrm{Fe}^{3+}$ ions. The latter behaves as an acid:
$$\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+}(a q) \rightleftharpoons \mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5} \mathrm{OH}^{2+}(a q)+\mathrm{H}^{+}(a q)$$
a. Calculate the expected osmotic pressure of this solution at $25^{\circ} \mathrm{C}$ if the above dissociation is negligible.
b. The actual osmotic pressure of the solution is 6.73 atm at $25^{\circ} \mathrm{C} .$ Calculate $K_{\mathrm{a}}$ for the dissociation reaction of $\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+} .$ (To do this calculation, you must assume that none of the ions go through the semipermeable membrane. Actually, this is not a great assumption for the tiny $\mathrm{H}^{+}$ ion.)

James Irizarry
James Irizarry
Numerade Educator
03:51

Problem 187

A $2.14-\mathrm{g}$ sample of sodium hypoiodite is dissolved in water to make 1.25 L of solution. The solution $\mathrm{pH}$ is $11.32 .$ What is $K_{\mathrm{b}}$ for the hypoiodite ion?

Anatole Borisov
Anatole Borisov
Numerade Educator
04:42

Problem 188

Isocyanic acid (HNCO) can be prepared by heating sodium cyanate in the presence of solid oxalic acid according to the equation
$$2 \mathrm{NaOCN}(s)+\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(s) \longrightarrow 2 \mathrm{HNCO}(l)+\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(s)$$
Upon isolating pure HNCO(I), an aqueous solution of HNCO can be prepared by dissolving the liquid HNCO in water. What is the $\mathrm{pH}$ of a $100 .$ -mL solution of HNCO prepared from the reaction of $10.0 \mathrm{g}$ each of $\mathrm{NaOCN}$ and $\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4},$ assuming all of the HNCO produced is dissolved in solution? $(K_{\mathrm{a}}$ of HNCO $\left.=1.2 \times 10^{-4} .\right)$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:58

Problem 189

A certain acid, HA, has a vapor density of $5.11 \mathrm{g} / \mathrm{L}$ when in the gas phase at a temperature of $25^{\circ} \mathrm{C}$ and a pressure of 1.00 atm. When 1.50 g of this acid is dissolved in enough water to make 100.0 mL of solution, the $p$ H is found to be $1.80 .$ Calculate $K_{\mathrm{a}}$ for the acid.

Ronald Prasad
Ronald Prasad
Numerade Educator
08:44

Problem 190

An aqueous solution contains a mixture of 0.0500 $M$ HCOOH $\left(K_{\mathrm{a}}=1.77 \times 10^{-4}\right)$ and $0.150 M \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COOH}\left(K_{\mathrm{a}}=1.34 \times\right.$
$10^{-5}$ ). Calculate the $p$ H of this solution. Because both acids are of comparable strength, the $\mathrm{H}^{+}$ contribution from both acids must be considered.

James Irizarry
James Irizarry
Numerade Educator
View

Problem 191

For the following, mix equal volumes of one solution from Group I with one solution from Group II to achieve the indicated pH. Calculate the pH of each solution.
Group I: $0.20 M \mathrm{NH}_{4} \mathrm{Cl}, 0.20 \mathrm{M} \mathrm{HCl}, 0.20 \mathrm{M} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3} \mathrm{Cl}$
$0.20 M\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{3} \mathrm{NHCl}$
Group II: $0.20 M$ KOI, $0.20 M$ NaCN, $0.20 M$ KOCI, $0.20 M$ $\mathrm{NaNO}_{2}$
a. the solution with the lowest $\mathrm{pH}$
b. the solution with the highest $\mathrm{pH}$
c. the solution with the pH closest to 7.00

Susan Hallstrom
Susan Hallstrom
Numerade Educator