Holt: Modern Chemistry

Mickey Sarquis, Jerry L. Sarquis

Chapter 15 Acid-Base Titration and pH - all with Video Answers

Educators

Chapter Questions

00:46

Problem 1

Why is pure water a very weak electric conductor?

Mehrnaz Siavoshi

Numerade Educator

00:42

Problem 2

What does it mean when the formula of a particular ion or molecule is enclosed in brackets?

Mehrnaz Siavoshi

Numerade Educator

01:59

Problem 3

a. What is the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ of pure water at $25^{\circ} \mathrm{C} ?$
b. Is this true at all temperatures? Why or why not?

Mehrnaz Siavoshi

Numerade Educator

01:39

a. What is always true about the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ value of acidic solutions?
b. What is true about the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ value of acidic solutions at $25^{\circ} \mathrm{C} ?$

Mehrnaz Siavoshi

Numerade Educator

01:45

Problem 5

a. Describe what is meant by the pH of a solution.
b. Write the equation for determining pH.
c. Explain and illustrate what is meant by the common logarithm of a number.

Mehrnaz Siavoshi

Numerade Educator

02:38

Problem 6

Identify each of the following solutions that are at $25^{\circ} \mathrm{C}$ as acidic, basic, or neutral:
a. $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]=1.0 \times 10^{-7} \mathrm{M}$
b. $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]=1.0 \times 10^{-10} \mathrm{M}$
c. $\left[\mathrm{OH}^{-}\right]=1.0 \times 10^{-7} \mathrm{M}$
d. $\left[\mathrm{OH}^{-}\right]=1.0 \times 10^{-11} \mathrm{M}$
e. $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]=\left[\mathrm{OH}^{-}\right]$
f. $\mathrm{pH}=3.0$
g. $\mathrm{pH}=13.0$

Mehrnaz Siavoshi

Numerade Educator

01:56

Problem 7

Arrange the following common substances in order of increasing pH:
a. eggs
b. apples
c. tomatoes
d. milk
e. bananas
f. potatoes
g. lemons
h. milk of magnesia
i. sea water

Mehrnaz Siavoshi

Numerade Educator

03:18

Problem 8

Calculate the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ and $\left[\mathrm{OH}^{-}\right]$ for each of the following. (Hint: See Sample Problem A.)
a. 0.030 $\mathrm{M} \mathrm{HCl}$
b. $1.0 \times 10^{-4} \mathrm{M} \mathrm{NaOH}$
c. $5.0 \times 10^{-3} \mathrm{M} \mathrm{HNO}_{3}$
d. 0.010 $\mathrm{M} \mathrm{Ca}(\mathrm{OH})_{2}$

Mehrnaz Siavoshi

Numerade Educator

02:09

Problem 9

Determine the pH of each of the following solutions. (Hint: See Sample Problem B.)
a. $1.0 \times 10^{-2} \mathrm{M} \mathrm{HCl}$
b. $1.0 \times 10^{-3} \mathrm{M} \mathrm{HNO}_{3}$
c. $1.0 \times 10^{-5} \mathrm{M} \mathrm{HI}$
d. $1.0 \times 10^{-4} \mathrm{M} \mathrm{HBr}$

Mehrnaz Siavoshi

Numerade Educator

03:51

Problem 10

Given the following $\left[\mathrm{OH}^{-}\right]$ values, determine the pH of each solution.
a. $1.0 \times 10^{-6} \mathrm{M}$
b. $1.0 \times 10^{-9} \mathrm{M}$
c. $1.0 \times 10^{-2} \mathrm{M}$
d. $1.0 \times 10^{-7} \mathrm{M}$

Mehrnaz Siavoshi

Numerade Educator

02:57

Problem 11

Determine the pH of each solution.
a. $1.0 \times 10^{-2} \mathrm{M} \mathrm{NaOH}$
b. $1.0 \times 10^{-3} \mathrm{M} \mathrm{M} \mathrm{KOH}$
c. $1.0 \times 10^{-4} \mathrm{M} \mathrm{LiOH}$

Mehrnaz Siavoshi

Numerade Educator

01:22

Problem 12

Determine the pH of solutions with each of the following $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right] .$ (Hint: See Sample Problem C.)
a. $2.0 \times 10^{-5} \mathrm{M}$
b. $4.7 \times 10^{-7} \mathrm{M}$
c. $3.8 \times 10^{-3} \mathrm{M}$

Mehrnaz Siavoshi

Numerade Educator

02:21

Problem 14

Given the following pH values, determine the $\left[\mathrm{OH}^{-}\right]$ for each solution.
a. 7.00
b. 11.00
c. 4.00
d. 6.00

Mehrnaz Siavoshi

Numerade Educator

02:17

Problem 15

Determine $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ for solutions with the following pH values. $(\text { Hint: See sample Problem E.) }$
a. 4.23
b. 7.65
c. 9.48

Mehrnaz Siavoshi

Numerade Educator

06:22

Problem 16

A nitric acid solution is found to have a pH of 2.70. Determine each of the following:
a. $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$
b. $\left[\mathrm{OH}^{-}\right]$
c. the number of moles of HNO $_{3}$ required to prepare 5.50 L of this solution
d. the mass of HNO $_{3}$ in the solution in part $(\mathrm{c})$
e. the mililititers of concentrated acid needed to prepare the solution in part $(\mathrm{c})$ (Concentrated nitric acid is 69.5$\% \mathrm{HNO}_{3}$ by mass and has a density of 1.42 $\mathrm{g} / \mathrm{mL.} )$

Mehrnaz Siavoshi

Numerade Educator

00:52

Problem 17

What is meant by the transition interval of an indicator?

Mehrnaz Siavoshi

Numerade Educator

01:20

Problem 18

Explain how changes in pH affect the color of an indicator.

Mehrnaz Siavoshi

Numerade Educator

01:01

Problem 19

a. Without using an indicator, how can you determine the equivalence point of a titration experiment or the pH of a solution?
b. What can be observed about the rate of change of the pH of a solution near the end point of a titration?

Mehrnaz Siavoshi

Numerade Educator

02:08

Problem 20

a. What is meant by the end point of a titration?
b. What is the role of an indicator in the titration process?
c. On what basis is an indicator selected for a particular titration experiment?

Mehrnaz Siavoshi

Numerade Educator

02:17

Problem 21

For each of the four possible types of acid-base titration combinations (strong-strong, strong-weak, etc.), indicate the approximate pH at the end point. Also name a suitable indicator for detecting that end point.

Mehrnaz Siavoshi

Numerade Educator

02:35

Problem 22

Use Figures 2.7a and 2.7b to sketch the pH curve of a strong acid being titrated by a weak base.

David Collins

Numerade Educator

01:23

Problem 23

An unknown solution is colorless when tested with phenolphthalein but causes the indicator phenol red to turn red. Use this information to find the approximate pH of this solution.

Mehrnaz Siavoshi

Numerade Educator

02:47

Problem 24

For each of the following acid-base titration combinations, determine the number of moles of the first substance listed that would be the chemically equivalent amount of the second substance.
a. NaOH with 1.0 $\mathrm{mol} \mathrm{HCl}$
b. $\mathrm{HNO}_{3}$ with 0.75 $\mathrm{mol} \mathrm{KOH}$
c. $\mathrm{Ba}(\mathrm{OH})_{2}$ with 0.20 $\mathrm{mol} \mathrm{HF}$
d. $\mathrm{H}_{2} \mathrm{SO}_{4}$ with 0.90 $\mathrm{mol} \mathrm{Mg}(\mathrm{OH})_{2}$

Mehrnaz Siavoshi

Numerade Educator

02:16

Problem 25

Suppose that 15.0 $\mathrm{mL}$ of $2.50 \times 10^{-2} \mathrm{M}$ aqueous $\mathrm{H}_{2} \mathrm{SO}_{4}$ is required to neutralize 10.0 $\mathrm{mL}$ of an aqueous solution of KOH. What is the molarity of the KOH solution? (Hint: See Sample Problem F.)

Mehrnaz Siavoshi

Numerade Educator

02:32

Problem 26

In a titration experiment, a 12.5 $\mathrm{mL}$ sample of $1.75 \times 10^{-2} \mathrm{M} \mathrm{Ba}(\mathrm{OH})_{2}$ just neutralized 14.5 $\mathrm{mL}$ of $\mathrm{HNO}_{3}$ solution. Calculate the molarity of the $\mathrm{HNO}_{3}$ solution.

Mehrnaz Siavoshi

Numerade Educator

01:37

Problem 27

a. What is the $\left[\mathrm{OH}^{-}\right]$ of a $4.0 \times 10^{-4} \mathrm{M}$ solution of $\mathrm{Ca}(\mathrm{OH})_{2} ?$
b. What is the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ of the solution?

Mehrnaz Siavoshi

Numerade Educator

02:00

Problem 28

Given the following $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ values, determine the pH of each solution.
a. $1.0 \times 10^{-7} \mathrm{M}$
b. $1.0 \times 10^{-3} \mathrm{M}$
c. $1.0 \times 10^{-12} \mathrm{M}$
d. $1.0 \times 10^{-5} \mathrm{M}$

Mehrnaz Siavoshi

Numerade Educator

00:44

Problem 29

What is the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ for a solution that has a pH of 6.0$?$

Mehrnaz Siavoshi

Numerade Educator

01:40

Problem 30

Suppose that a 5.0 $\times 10^{-5}$ M solution of Ba(OH) $_{2}$ is prepared. What is the pH of the solution?

Mehrnaz Siavoshi

Numerade Educator

View

Problem 30

Suppose that a 5.0 $\times 10^{-5}$ M solution of Ba(OH) $_{2}$ is prepared. What is the pH of the solution?

Mehrnaz Siavoshi

Numerade Educator

01:35

Problem 31

a. Calculate the pH of a solution that has an $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ of $8.4 \times 10^{-11} \mathrm{M} .$
b. Calculate the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ of a solution that has a pH of 2.50 .

Mehrnaz Siavoshi

Numerade Educator

01:42

Problem 32

a. What is the concentration of $\mathrm{OH}^{-}$ in a $5.4 \times 10^{-5}$ M solution of magnesium hydroxide, Mg(OH) $_{2}$ ?
b. Calculate the concentration of $\mathrm{H}_{3} \mathrm{O}^{+}$ for this solution.

Mehrnaz Siavoshi

Numerade Educator

01:23

Problem 33

a. Calculate the molarity of $\mathrm{H}_{3} \mathrm{O}^{+}$ in a solution that has a ph of $8.90 .$
b. Calculate the concentration of $\mathrm{OH}^{-}$ for this solution.

Mehrnaz Siavoshi

Numerade Educator

01:08

Problem 34

What is the pH of a solution in which [OH- $]$ equals $6.9 \times 10^{-10} \mathrm{M} ?$

Mehrnaz Siavoshi

Numerade Educator

02:35

Problem 35

In a titration, 25.9 $\mathrm{mL}$ of $3.4 \times 10^{-3} \mathrm{M} \mathrm{Ba}(\mathrm{OH})_{2}$ neutralized 16.6 $\mathrm{mL}$ of HCl solution. What is the molarity of the HCl solution?

Mehrnaz Siavoshi

Numerade Educator

02:10

Problem 36

Find the molarity of a Ca $\mathrm{Ca}(\mathrm{OH})_{2}$ solution given that 428 $\mathrm{mL}$ of the solutio is neutralized in a titration by 115 $\mathrm{mL}$ of $6.7 \times 10^{-3} \mathrm{M} \mathrm{H} \mathrm{NO}_{3} .$

Mehrnaz Siavoshi

Numerade Educator

01:55

Problem 37

Suppose that 10.1 $\mathrm{mL}$ of $\mathrm{HNO}_{3}$ is neutralized by 71.4 $\mathrm{mL}$ of a $4.2 \times 10^{-3} \mathrm{M}$ solution of KOH in a titration. Calculate the concentration of the HNO $_{3}$ solution.

Mehrnaz Siavoshi

Numerade Educator

02:37

Problem 38

Interpreting Graphics The following titration curve resulted from the titration of an unknown acid with 0.10 M NaOH. Analyze the curve. Make inferences related to the type of acidic solution titrated.

Ronald Prasad

Numerade Educator

01:47

Problem 39

The normal pH of blood is about 7.4. When the pH shifts above or below that level, the results are acidosis or alkalosis. Review the section on blood pH in Group 14 of the Elements Handbook (Appendix A), and answer the following.
a. What chemical species keep $\mathrm{H}_{3} \mathrm{O}^{+}$ in blood at the appropriate $\mathrm{pH}$ ?
b. What condition results when there is an excess of $\mathrm{CO}_{2}$ in the blood?
c. What is hyperventilation and how does it affect blood pH?

Mehrnaz Siavoshi

Numerade Educator

13:33

Problem 40

Examine the labels of at least five brands of shampoo. Note what is written there, if anything, regarding the pH of the shampoo. Do library research to find out why such pH ranges are chosen and why other ranges might be harmful to hair or eyes.

Dr. Satish Ingale

Numerade Educator

01:41

Problem 41

Acid rain is an environmental issue that crosses state and national boundaries. Conduct library research on this topic and write a brief report. Include a description of the areas in the United States affected by acid rain, and the geographical source of the sulfur and nitrogen oxides that are responsible for acid rain in each region.

Manik Pulyani

Numerade Educator

19:46

Problem 42

Performance Use pH paper to determine the approximate pH of various brands of orange juice, which contains citric acid.

Shubham Kumar

Numerade Educator

03:11

Problem 43

Performance Design and conduct an experiment to extract possible acid-base indicators from sources such as red cabbage, berries, and flower petals. Use known acidic, basic, and neutral solutions to test the action of each indicator that you are able to isolate.

Ronald Prasad

Numerade Educator