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CHEMISTRY: The Molecular Nature of Matter and Change 2016

Martin S. Silberberg, Patricia G. Amateis

Chapter 18

Acid-Base Equilibria

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Problem 1

What is the role of water in the Arrhenius acid-base definition?

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Problem 2

What do Arrhenius acids have in common? What do Arrhenius bases have in common? Explain neutralization in terms of the Arrhenius acid-base definition. What data led Arrhenius to propose this idea of neutralization?

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Problem 3

Why is the Arrhenius acid-base definition too limited? Give an example for which the Arrhenius definition does not apply.

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Problem 4

What do "strong" and "weak" mean for acids and bases? $K_{\mathrm{a}}$ values of weak acids vary over more than 10 orders of magnitude. What do the acids have in common that makes them "weak"?

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Problem 5

Which of the following are Arrhenius acids?
(a) $\mathrm{H}_{2} \mathrm{O} \quad$ (b) $\mathrm{Ca}(\mathrm{OH})_{2} \quad$ (c) $\mathrm{H}_{3} \mathrm{PO}_{3} \quad$ (d) $\mathrm{HI}$

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Problem 6

Which of the following are Arrhenius acids?
(a) $\mathrm{NaHSO}_{4} \quad$ (b) $\mathrm{CH}_{4} \quad$ (c) $\mathrm{NaH} \quad$ (d) $\mathrm{H}_{3} \mathrm{N}$

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Problem 7

Which of the following are Arrhenius bases?
(a) $\mathrm{H}_{3} \mathrm{AsO}_{4} \quad$ (b) $\mathrm{Ba}(\mathrm{OH})_{2} \quad$ (c) $\mathrm{HClO} \quad$ (d) $\mathrm{KOH}$

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Problem 8

Which of the following are Arrhenius bases?
(a) $\mathrm{CH}_{3} \mathrm{COOH} \quad$ (b) $\mathrm{HOH} \quad$ (c) $\mathrm{CH}_{3} \mathrm{OH} \quad$ (d) $\mathrm{H}_{2} \mathrm{NNH}_{2}$

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Problem 9

Write the $K_{\mathrm{a}}$ expression for each of the following in water:
(a) $\mathrm{HCN} \quad$ (b) $\mathrm{HCO}_{3}^{-} \quad$ (c) $\mathrm{HCOOH}$

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Problem 10

Write the $K_{\mathrm{a}}$ expression for each of the following in water:
(a) $\mathrm{CH}_{3} \mathrm{NH}_{3}^{+} \quad$ (b) $\mathrm{HClO}$ $\quad$ (c) $\mathrm{H}_{2} \mathrm{S}$

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Problem 11

Write the $K_{\mathrm{a}}$ expression for each of the following in water:
(a) $\mathrm{HNO}_{2} \quad$ (b) $\mathrm{CH}_{3} \mathrm{COOH} \quad$ (c) $\mathrm{HBrO}_{2}$

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Problem 12

Write the $K_{\mathrm{a}}$ expression for each of the following in water:
(a) $\mathrm{H}_{2} \mathrm{PO}_{4}^{-} \quad$ (b) $\mathrm{H}_{3} \mathrm{PO}_{2} \quad$ (c) $\mathrm{HSO}_{4}^{-}$

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Problem 13

Use Appendix C to rank the following in order of increasing acid strength: $\mathrm{HIO}_{3}, \mathrm{HI}, \mathrm{CH}_{3} \mathrm{COOH}, \mathrm{HF}$

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Problem 14

Use Appendix C to rank the following in order of decreasing acid strength: $\mathrm{HClO}, \mathrm{HCl}, \mathrm{HCN}, \mathrm{HNO}_{2}$

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Problem 15

Classify each as a strong or weak acid or base:
(a) $\mathrm{H}_{3} \mathrm{AsO}_{4} \quad$ (b) $\mathrm{Sr}(\mathrm{OH})_{2} \quad$ (c) $\mathrm{HIO}$ $\quad$ (d) $\mathrm{HClO}_{4}$

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Problem 16

Classify each as a strong or weak acid or base:
(a) $\mathrm{CH}_{3} \mathrm{NH}_{2} \quad$ (b) $\mathrm{K}_{2} \mathrm{O} \quad$ (c) $\mathrm{HI} \quad$ (d) $\mathrm{HCOOH}$

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Problem 17

Classify each as a strong or weak acid or base:
(a) $\mathrm{RbOH} \quad$ (b) $\mathrm{HBr} \quad$ (c) $\mathrm{H}_{2} \mathrm{Te} \quad$ (d) $\mathrm{HClO}$

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Problem 18

Classify each as a strong or weak acid or base:
(a) $\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2} \quad$ (b) $\mathrm{H}_{2} \mathrm{SeO}_{4} \quad$ (c) $\mathrm{HS}^{-} \quad$ (d) $\mathrm{B}(\mathrm{OH})_{3}$

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Problem 19

What is an autoionization reaction? Write equations for the autoionization reactions of $\mathrm{H}_{2} \mathrm{O}$ and of $\mathrm{H}_{2} \mathrm{SO}_{4}.$

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Problem 20

What is the difference between $K_{\mathrm{c}}$ and $K_{\mathrm{w}}$ for the autoionization of water?

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Problem 21

(a) What is the change in pH when $\left[\mathrm{OH}^{-}\right]$ increases by a factor of 10$?$ (b) What is the change in $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ when the pH decreases by 3 units?

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Problem 22

Which solution has the higher pH? Explain.

(a) $\mathrm{A}$ 0.1 $\mathrm{M}$ solution of an acid with $\mathrm{K}_{\mathrm{a}}=1 \times 10^{-4}$ or one with $K_{\mathrm{a}}=4 \times 10^{-5}$
(b) A 0.1 $\mathrm{M}$ solution of an acid with $\mathrm{p} K_{\mathrm{a}}=3.0$ or one with $\mathrm{p} K_{\mathrm{a}}=3.5$
(c) A 0.1$M$ solution or a 0.01$M$ solution of a weak acid
(d) A 0.1$M$ solution of a weak acid or a 0.1$M$ solution of a strong acid
(e) A 0.1$M$ solution of an acid or a 0.01$M$ solution of a base
(f) A solution of pOH 6.0 or one of pOH 8.0

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Problem 23

(a) What is the pH of 0.0111$M$ $\mathrm{NaOH} ?$ Is the solution neutral, acidic, or basic? (b) What is the pOH of $1.35 \times 10^{-3} M$ $\mathrm{HCl}$? Is the solution neutral, acidic, or basic?

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Problem 24

(a) What is the pH of 0.0333 $M$ $\mathrm{HNO}_{3} ?$ Is the solution neutral, acidic, or basic? (b) What is the pOH of 0.0347$M$ $\mathrm{KOH}$ ? Is the solution neutral, acidic, or basic?

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Problem 25

(a) What is the ph of $6.14 \times 10^{-3}$ $M$ $\mathrm{HI}$? Is the solution neeutral, acidic, or basic? (b) What is the pOH of 2.55 $M \mathrm{Ba}(\mathrm{OH})_{2}$ ? Is the solution neutral, acidic, or basic?

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Problem 26

(a) What is the pH of $7.52 \times 10^{-4} M$ $\mathrm{CsOH} ?$ Is the solution neutral, acidic, or basic? (b) What is the pOH of $1.59 \times 10^{-3} M$ $\mathrm{HClO}_{4} ?$ Is the solution neutral, acidic, or basic?

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Problem 27

(a) What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pOH}$ in a solution with $\mathrm{a} \mathrm{pH}$ of 9.85$?(\mathrm{b})$ What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pH}$ in a solution with a pOH of 9.43$?$

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Problem 28

(a) What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pOH}$ in a solution with $\mathrm{a} \mathrm{pH}$ of 3.47$?(\mathrm{b})$ What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pH}$ in a solution with a pOH of 4.33$?$

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Problem 29

(a) What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pOH}$ in a solution with $\mathrm{a} \mathrm{pH}$ of 4.77$?(\mathrm{b})$ What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pH}$ in a solution with a pOH of 5.65$?$

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Problem 30

(a) What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pOH}$ in a solution with $\mathrm{a} \mathrm{pH}$ of 8.97? (b) What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pH}$ in a solution with a $\mathrm{pOH}$ of 11.27$?$

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Problem 31

How many moles of $\mathrm{H}_{3} \mathrm{O}^{+}$ or $\mathrm{OH}^{-}$ must you add to a liter of $\mathrm{HA}$ solution to adjust its $\mathrm{pH}$ from 3.15 to 3.65$?$ Assume a negligible volume change.

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Problem 32

How many moles of $\mathrm{H}_{3} \mathrm{O}^{+}$ or $\mathrm{OH}^{-}$ must you add to a liter of $\mathrm{HA}$ solution to adjust its $\mathrm{pH}$ from 9.33 to 9.07$?$ Assume a negligible volume change.

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Problem 33

How many moles of $\mathrm{H}_{3} \mathrm{O}^{+}$ or $\mathrm{OH}^{-}$ must you add to 5.6 $\mathrm{L}$ of $\mathrm{HA}$ solution to adjust its $\mathrm{pH}$ from 4.52 to 5.25$?$ Assume a negligible volume change.

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Problem 34

How many moles of $\mathrm{H}_{3} \mathrm{O}^{+}$ or $\mathrm{OH}^{-}$ must you add to 87.5 $\mathrm{mL}$ of $\mathrm{HA}$ solution to adjust its $\mathrm{pH}$ from 8.92 to 6.33$?$ Assume a negligible volume change.

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Problem 35

The two molecular scenes below depict the relative concentrations of $\mathrm{H}_{3} \mathrm{O}^{+}$ (purple) in solutions of the same volume (with counter ions and solvent molecules omitted for clarity). If the pH in scene A is 4.8, what is the pH in scene B?

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Problem 36

Like any equilibrium constant, $K_{\mathrm{w}}$ changes with temperature. (a) Given that autoionization is endothermic, how does $K_{\mathrm{w}}$ change with rising $T ?$ Explain with a reaction that includes heat as reactant or product. (b) In many medical applications, the value of $K_{\mathrm{w}}$ at $37^{\circ} \mathrm{C}$ (body temperature) may be more appropriate than the
value at $25^{\circ} \mathrm{C}, 1.0 \times 10^{-14} .$ The pH of pure water at $37^{\circ} \mathrm{C}$ is $6.80 .$ Calculate $K_{\mathrm{w}}, \mathrm{pOH}$ , and $\left[\mathrm{OH}^{-}\right]$ at this temperature.

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Problem 37

How are the Arrhenius and Bronsted-Lowry acid-base definitions different? How are they similar? Name two Bronsted-Lowry bases that are not Arrhenius bases. Can you do the same for acids? Explain.

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Problem 38

What is a conjugate acid-base pair? What is the relationship between the two members of the pair?

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Problem 39

(a) A Bronsted-Lowry acid-base reaction proceeds in the net direction in which a stronger acid and stronger base form a weaker acid and weaker base. Explain.
(b) The molecular scene at right depicts an aqueous solution of two conjugate acid-base pairs: $\mathrm{HA} / \mathrm{A}^{-}$ and $\mathrm{HB} / \mathrm{B}^{-}$ . The base in the first pair is represented by red spheres, and the base in the second pair by green spheres; solvent molecules are omitted for clarity. Which is the stronger acid? Stronger base? Explain.

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Problem 40

What is an amphiprotic species? Name one and write balanced equations that show why it is amphiprotic.

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Problem 41

Write balanced equations and $K_{\mathrm{a}}$ expressions for these Bronsted-Lowry acids in water:
(a) $\mathrm{H}_{3} \mathrm{PO}_{4} \quad$ (b) $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COOH} \quad$ (c) $\mathrm{HSO}_{4}^{-}$

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Problem 42

Write balanced equations and $K_{\mathrm{a}}$ expressions for these Bronsted-Lowry acids in water:
(a) $\mathrm{HCOOH} \quad$ (b) $\mathrm{HClO}_{3} \quad$ (c) $\mathrm{H}_{2} \mathrm{AsO}_{4}^{-}$

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Problem 43

Give the formula of the conjugate base:
(a) $\mathrm{HCl} \quad$ (b) $\mathrm{H}_{2} \mathrm{CO}_{3} \quad$ (c) $\mathrm{H}_{2} \mathrm{O}$

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Problem 44

Give the formula of the conjugate base:
(a) $\mathrm{HPO}_{4}^{2-} \quad$ (b) $\mathrm{NH}_{4}^{+} \quad(\mathrm{c}) \mathrm{HS}^{-}$

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Problem 45

Give the formula of the conjugate acid:
(a) $\mathrm{NH}_{3} \quad$ (b) $\mathrm{NH}_{2}^{-} \quad$ (c) nicotine, $\mathrm{C}_{10} \mathrm{H}_{14} \mathrm{N}_{2}$

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Problem 46

Give the formula of the conjugate acid:
(a) $\mathrm{O}^{2-} \quad$ (b) $\mathrm{SO}_{4}^{2-} \quad$ (c) $\mathrm{H}_{2} \mathrm{O}$

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Problem 47

In each equation, label the acids, bases, and conjugate pairs:
(a) $\mathrm{HCl}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{Cl}^{-}+\mathrm{H}_{3} \mathrm{O}^{+}$
(b) HClO_ $_{4}+\mathrm{H}_{2} \mathrm{SO}_{4} \rightleftharpoons \mathrm{ClO}_{4}^{-}+\mathrm{H}_{3} \mathrm{SO}_{4}^{+}$
(c) $\mathrm{HPO}_{4}^{2-}+\mathrm{H}_{2} \mathrm{SO}_{4} \rightleftharpoons \mathrm{H}_{2} \mathrm{PO}_{4}^{-}+\mathrm{HSO}_{4}^{-}$

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Problem 48

In each equation, label the acids, bases, and conjugate pairs:
(a) $\mathrm{NH}_{3}+\mathrm{HNO}_{3} \rightleftharpoons \mathrm{NH}_{4}^{+}+\mathrm{NO}_{3}^{-}$
(b) $\mathrm{O}^{2-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{OH}^{-}+\mathrm{OH}^{-}$
(c) $\mathrm{NH}_{4}^{+}+\mathrm{BrO}_{3}^{-} \rightleftharpoons \mathrm{NH}_{3}+\mathrm{HBrO}_{3}$

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Problem 49

In each equation, label the acids, bases, and conjugate pairs:
(a) $\mathrm{NH}_{3}+\mathrm{H}_{3} \mathrm{PO}_{4} \rightleftharpoons \mathrm{NH}_{4}^{+}+\mathrm{H}_{2} \mathrm{PO}_{4}^{-}$
(b) $\mathrm{CH}_{3} \mathrm{O}^{-}+\mathrm{NH}_{3} \rightleftharpoons \mathrm{CH}_{3} \mathrm{OH}+\mathrm{NH}_{2}^{-}$
(c) $\mathrm{HPO}_{4}^{2-}+\mathrm{HSO}_{4}=\mathrm{H}_{2} \mathrm{PO}_{4}^{-}+\mathrm{SO}_{4}^{2-}$

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Problem 50

In each equation, label the acids, bases, and conjugate pairs:
(a) $\mathrm{NH}_{4}^{+}+\mathrm{CN}^{-} \rightleftharpoons \mathrm{NH}_{3}+\mathrm{HCN}$
(b) $\mathrm{H}_{2} \mathrm{O}+\mathrm{HS}^{-} \Longrightarrow \mathrm{OH}^{-}+\mathrm{H}_{2} \mathrm{S}$
(c) $\mathrm{HSO}_{3}^{-}+\mathrm{CH}_{3} \mathrm{NH}_{2} \rightleftharpoons \mathrm{SO}_{3}^{2-}+\mathrm{CH}_{3} \mathrm{NH}_{3}^{+}$

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Problem 51

Write balanced net ionic equations for the following reactions, and label the conjugate acid-base pairs:

(a) $\mathrm{NaOH}(a q)+\mathrm{NaH}_{2} \mathrm{PO}_{4}(a q) \rightleftharpoons \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{Na}_{2} \mathrm{HPO}_{4}(a q)$
(b) $\mathrm{KHSO}_{4}(a q)+\mathrm{K}_{2} \mathrm{CO}_{3}(a q) \rightleftharpoons \mathrm{K}_{2} \mathrm{SO}_{4}(a q)+\mathrm{KHCO}_{3}(a q)$

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Problem 52

Write balanced net ionic equations for the following reactions, and label the conjugate acid-base pairs:

(a) HNO $_{3}(a q)+\mathrm{Li}_{2} \mathrm{CO}_{3}(a q) \rightleftharpoons \mathrm{LiNO}_{3}(a q)+\mathrm{LiHCO}_{3}(a q)$
(b) $2 \mathrm{NH}_{4} \mathrm{Cl}(a q)+\mathrm{Ba}(\mathrm{OH})_{2}(a q) \rightleftharpoons 2 \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{BaCl}_{2}(a q)+2 \mathrm{NH}_{3}(a q)$

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Problem 53

The following aqueous species constitute two conjugate acid-base pairs. Use them to write one acid-base reaction with $K_{\mathrm{c}}>1$ and another with $K_{\mathrm{c}}<1 : \mathrm{HS}^{-}, \mathrm{Cl}^{-}, \mathrm{HCl}, \mathrm{H}_{2} \mathrm{S}.$

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Problem 54

The following aqueous species constitute two conjugate acid-base pairs. Use them to write one acid-base reaction with $K_{\mathrm{c}}>1$ and another with $K_{\mathrm{c}}<1 : \mathrm{NO}_{3}^{-}, \mathrm{F}^{-}, \mathrm{HF}, \mathrm{HNO}_{3}.$

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Problem 55

Use Figure 18.8$(\mathrm{p} .790)$ to determine whether $K_{\mathrm{c}}>1$ for
(a) $\mathrm{HCl}+\mathrm{NH}_{3} \rightleftharpoons \mathrm{NH}_{4}^{+}+\mathrm{Cl}^{-}$
(b) $\mathrm{H}_{2} \mathrm{SO}_{3}+\mathrm{NH}_{3} \rightleftharpoons \mathrm{HSO}_{3}^{-}+\mathrm{NH}_{4}^{+}$

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Problem 56

Use Figure 18.8$(\mathrm{p} .790)$ to determine whether $K_{\mathrm{c}}>1$ for
(a) $\mathrm{OH}^{-}+\mathrm{HS}^{-} \rightleftharpoons \mathrm{H}_{2} \mathrm{O}+\mathrm{S}^{2-}$
(b) $\mathrm{HCN}+\mathrm{HCO}_{3}^{-} \rightleftharpoons \mathrm{H}_{2} \mathrm{CO}_{3}+\mathrm{CN}^{-}$

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Problem 57

Use Figure 18.8$(\mathrm{p} .790)$ to determine whether $K_{\mathrm{c}}<1$ for
(a) $\mathrm{NH}_{4}^{+}+\mathrm{HPO}_{4}^{2-} \rightleftharpoons \mathrm{NH}_{3}+\mathrm{H}_{2} \mathrm{PO}_{4}^{-}$
(b) $\mathrm{HSO}_{3}^{-}+\mathrm{HS}^{-} \rightleftharpoons \mathrm{H}_{2} \mathrm{SO}_{3}+\mathrm{S}^{2-}$

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Problem 58

Use Figure 18.8$(\mathrm{p} .790)$ to determine whether $K_{\mathrm{c}}<1$ for
(a) $\mathrm{H}_{2} \mathrm{PO}_{4}^{-}+\mathrm{F}^{-} \rightleftharpoons \mathrm{HPO}_{4}^{2-}+\mathrm{HF}$
(b) $\mathrm{CH}_{3} \mathrm{COO}^{-}+\mathrm{HSO}_{4}^{-} \rightleftharpoons \mathrm{CH}_{3} \mathrm{COOH}+\mathrm{SO}_{4}^{2-}$

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Problem 59

In each of the following cases, is the concentration of acid before and after dissociation nearly the same or very different? Explain your reasoning: (a) a concentrated solution of a strong acid; (b) a concentrated solution of a weak acid; (c) a dilute solution of a weak acid; (d) a dilute solution of a strong acid.

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Problem 60

A sample of 0.0001$M$ $\mathrm{HCl}$ has $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ close to that of a sample of 0.1 $M$ $\mathrm{CH}_{3} \mathrm{COOH} .$ Are acetic acid and hydrochloric
acid equally strong in these samples? Explain.

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Problem 61

A 0.15 $M$ solution of $\mathrm{HA}$ (blue and green) is 33% dissociated. Which of the scenes below represents a sample of that solution after it is diluted with water? (A real weak acid does not have a percent dissociation this high.)

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Problem 62

In which of the following solutions will $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ be approximately equal to $\left[\mathrm{CH}_{3} \mathrm{COO}^{-}\right] :$ (a) 0.1$M$ $\mathrm{CH}_{3} \mathrm{COOH};$ (b) $1 \times 10^{-7} M$ $\mathrm{CH}_{3} \mathrm{COOH} ;(\mathrm{c})$ a solution containing both 0.1 $M$ $\mathrm{CH}_{3} \mathrm{COOH}$ and 0.1 $M$ $\mathrm{CH}_{3} \mathrm{COONa}$ ? Explain.

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Problem 63

Why do successive $K_{\mathrm{a}}^{\prime}$ s decrease for all polyprotic acids?

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Problem 64

A 0.15$M$ solution of butanoic acid, $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH}$ , contains $1.51 \times 10^{-3} M$ $\mathrm{H}_{3} \mathrm{O}^{+} .$ What is the $K_{\mathrm{a}}$ of butanoic acid?

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Problem 65

A 0.035 $M$ solution of a weak acid $(\mathrm{HA})$ has a pH of $4.88 .$ What is the $K_{\mathrm{a}}$ of the acid?

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Problem 66

Nitrous acid, $\mathrm{HNO}_{2},$ has a $K_{\mathrm{a}}$ of $7.1 \times 10^{-4} .$ What are
$\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{NO}_{2}^{-}\right],$ and $\left[\mathrm{OH}^{-}\right]$ in 0.60 $\mathrm{M} \mathrm{HNO}_{2} ?$

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Problem 67

Hydrofluoric acid, $\mathrm{HF}$ , has a $K_{\mathrm{a}}$ of $6.8 \times 10^{-4} .$ What are
$\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{F}^{-}\right],$ and $\left[\mathrm{OH}^{-}\right]$ in 0.75 $M$ $\mathrm{HF} ?$

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Problem 68

Chloroacetic acid, $\mathrm{ClCH}_{2} \mathrm{COOH}$ , has a p $K_{\mathrm{a}}$ of $2.87 .$ What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right], \mathrm{pH},\left[\mathrm{ClCH}_{2} \mathrm{COO}^{-}\right],$ and $\left[\mathrm{ClCH}_{2} \mathrm{COOH}\right]$ in 1.25 $M$ $\mathrm{ClCH}_{2} \mathrm{COOH} ?$

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Problem 69

Hypochlorous acid,$\mathrm{HClO},$ has a $\mathrm{p} K_{\mathrm{a}}$ of $7.54 .$ What are $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right], \mathrm{pH},\left[\mathrm{ClO}^{-}\right],$ and $[\mathrm{HClO}]$ in 0.115 $M$ $\mathrm{HClO?}$

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Problem 70

In a 0.20$M$ solution, a weak acid is 3.0$\%$ dissociated.

(a) Calculate the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right], \mathrm{pH},\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pOH}$ of the solution.
(b) Calculate $K_{\mathrm{a}}$ of the acid.

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Problem 71

In a 0.735$M$ solution, a weak acid is 12.5$\%$ dissociated.

(a) Calculate the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right], \mathrm{pH},\left[\mathrm{OH}^{-}\right],$ and pOH of the solution.
(b) Calculate $K_{\mathrm{a}}$ of the acid.

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Problem 72

A 0.250 -mol sample of $\mathrm{HX}$ is dissolved in enough $\mathrm{H}_{2} \mathrm{O}$ to form 655 mL of solution. If the pH of the solution is $3.54,$ what is the $K_{\mathrm{a}}$ of $\mathrm{HX}$ ?

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Problem 73

A $4.85 \times 10^{-3}$ -mol sample of $\mathrm{HY}$ is dissolved in enough $\mathrm{H}_{2} \mathrm{O}$ to form 0.095 $\mathrm{L}$ of solution. If the pH of the solution is 2.68 what is the $K_{\mathrm{a}}$ of $\mathrm{HY} ?$

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Problem 74

The weak acid $\mathrm{HZ}$ has a $K_{\mathrm{a}}$ of $2.55 \times 10^{-4}$
(a) Calculate the $\mathrm{pH}$ of 0.075 $M$ $\mathrm{HZ}.$
(b) Calculate the pOH of 0.045$M$ $\mathrm{HZ}$ .

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Problem 75

The weak acid $\mathrm{HQ}$ has a $\mathrm{p} K_{\mathrm{a}}$ of 4.89.
(a) Calculate the $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ of $3.5 \times 10^{-2} M$ $\mathrm{HQ}$ .
(b) Calculate the $\left[\mathrm{OH}^{-}\right]$ of 0.65 $M$ $\mathrm{HQ}$ .

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Problem 76

(a) Calculate the pH of $0.175 M \mathrm{HY},$ if $K_{\mathrm{a}}=1.50 \times 10^{-4}$
(b) Calculate the pOH of $0.175 M \mathrm{HX},$ if $K_{\mathrm{a}}=2.00 \times 10^{-2}$

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Problem 77

(a) Calculate the pH of 0.55 $M \mathrm{HCN},$ if $K_{2}=6.2 \times 10^{-10}$
(b) Calculate the pOH of $0.044 M \mathrm{HO}_{3},$ if $K_{\mathrm{a}}=0.16$

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Problem 78

Use Appendix $\mathrm{C}$ to calculate the percent dissociation of 0.55 $M$ benzoic acid, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COOH} .$

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Problem 79

Use Appendix $\mathrm{C}$ to calculate the percent dissociation of 0.050$M$ $\mathrm{CH}_{3} \mathrm{COOH} .$

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Problem 80

Use Appendix $\mathrm{C}$ to calculate $\left[\mathrm{H}_{2} \mathrm{S}\right],\left[\mathrm{HS}^{-}\right],\left[\mathrm{S}^{2-}\right],\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],$ $\mathrm{pH},\left[\mathrm{OH}^{-}\right],$ and pOH in a 0.10$M$ solution of the diprotic acid hydrosulfuric acid.

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Problem 81

Use Appendix $\mathrm{C}$ to calculate $\left[\mathrm{H}_{2} \mathrm{C}_{3} \mathrm{H}_{2} \mathrm{O}\right],\left[\mathrm{HC}_{3} \mathrm{H}_{2} \mathrm{O}_{4}-\right],$ $\left[\mathrm{C}_{3} \mathrm{H}_{2} \mathrm{O}_{4}^{2-}\right],\left[\mathrm{H}_{3} \mathrm{O}^{+}\right], \mathrm{pH},\left[\mathrm{OH}^{-}\right],$ and $\mathrm{pOH}$ in a 0.200 $M$ solution of the diprotic acid malonic acid.

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Problem 82

Acetylsalicylic acid (aspirin), $\mathrm{HC}_{9} \mathrm{H}_{7} \mathrm{O}_{4},$ is the most widely used pain reliever and fever reducer. Find the pH of 0.018$M$ aqueous aspirin at body temperature $\left(K_{\mathrm{a}} \text { at } 37^{\circ} \mathrm{C}=3.6 \times 10^{-4}\right) .$

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Problem 83

Formic acid, $\mathrm{HCOOH}$, the simplest carboxylic acid, is used in the textile and rubber industries and is secreted as a defense by many species of ants (family Formicidae). Calculate the percent dissociation of 0.75 $M$ $\mathrm{HCOOH}$.

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Problem 84

Across a period, how does the electronegativity of a nonmetal affect the acidity of its binary hydride?

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Problem 85

How does the atomic size of a nonmetal affect the acidity of its binary hydride?

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Problem 86

A strong acid has a weak bond to its acidic proton, whereas a weak acid has a strong bond to its acidic proton. Explain.

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Problem 87

Perchloric acid, $\mathrm{HClO}_{4}$ is the strongest of the halogen oxo-acids, and hypoiodous acid, $\mathrm{HIO}$, is the weakest. What two factors govern this difference in acid strength?

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Problem 88

Choose the stronger acid in each of the following pairs:
(a) $\mathrm{H}_{2} \mathrm{SeO}_{3}$ or $\mathrm{H}_{2} \mathrm{SeO}_{4} \quad$ (b) $\mathrm{H}_{3} \mathrm{PO}_{4}$ or $\mathrm{H}_{3} \mathrm{AsO}_{4} \quad$ (c) $\mathrm{H}_{2} \mathrm{S}$ or $\mathrm{H}_{2} \mathrm{Te}$

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Problem 89

Choose the weaker acid in each of the following pairs:
(a) HBr or $\mathrm{H}_{2} \mathrm{Se} \quad$ (b) $\mathrm{HClO}_{4}$ or $\mathrm{H}_{2} \mathrm{SO}_{4} \quad$ (c) $\mathrm{H}_{2} \mathrm{SO}_{3}$ or $\mathrm{H}_{2} \mathrm{SO}_{4}$

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Problem 90

Choose the stronger acid in each of the following pairs:
(a) $\mathrm{H}_{2} \mathrm{Se}$ or $\mathrm{H}_{3} \mathrm{As} \quad$ (b) $\mathrm{B}(\mathrm{OH})_{3}$ or $\mathrm{Al}(\mathrm{OH})_{3} \quad$ (c) $\mathrm{HBrO}_{2}$ or $\mathrm{HBrO}$

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Problem 91

Choose the weaker acid in each of the following pairs:
(a) $\mathrm{HI}$ or $\mathrm{HBr} \quad$ (b) $\mathrm{H}_{3} \mathrm{AsO}_{4}$ or $\mathrm{H}_{2} \mathrm{SeO}_{4} \quad$ (c) $\mathrm{HNO}_{3}$ or $\mathrm{HNO}_{2}$

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Problem 92

Use Appendix C to choose the solution with the lower pH:
(a) 0.5$M \mathrm{CuBr}_{2}$ or 0.5$M \mathrm{AlBr}_{3}$
(b) 0.3$M \mathrm{ZnCl}_{2}$ or 0.3$M \mathrm{SnCl}_{2}$

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Problem 93

Use Appendix C to choose the solution with the lower pH:
(a) 0.1 $\mathrm{M} \mathrm{FeCl}_{3}$ or 0.1 $\mathrm{M} \mathrm{AlCl}_{3}$
(b) 0.1 $\mathrm{M} \mathrm{BeCl}_{2}$ or 0.1 $\mathrm{M} \mathrm{CaCl}_{2}$

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Problem 94

Use Appendix C to choose the solution with the higher pH:
(a) $0.2 M \mathrm{Ni}\left(\mathrm{NO}_{3}\right)_{2}$ or 0.2 $\mathrm{M} \mathrm{Co}\left(\mathrm{NO}_{3}\right)_{2}$
(b) $0.35 \mathrm{M} \mathrm{Al}\left(\mathrm{NO}_{3}\right)_{3}$ or 0.35 $\mathrm{M} \mathrm{Cr}\left(\mathrm{NO}_{3}\right)_{3}$

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Problem 95

Use Appendix C to choose the solution with the higher pH:
(a) 0.1$M \mathrm{NiCl}_{2}$ or 0.1 $M$ $\mathrm{NaCl}$
(b) 0.1$M$ $\mathrm{Sn}\left(\mathrm{NO}_{3}\right)_{2}$ or 0.1 $M$ $\mathrm{Co}\left(\mathrm{NO}_{3}\right)_{2}$

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Problem 96

What is the key structural feature of all Bronsted-Lowry bases? How does this feature function in an acid-base reaction?

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Problem 97

Why are most anions basic in $\mathrm{H}_{2} \mathrm{O} ?$ Give formulas of four anions that are not basic.

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Problem 98

Except for the $\mathrm{Na}^{+}$ spectator ion, aqueous solutions of $\mathrm{CH}_{3} \mathrm{COOH}$ and $\mathrm{CH}_{3} \mathrm{COONa}$ contain the same species. (a) What
are the species (other than $\mathrm{H}_{2} \mathrm{O} ) ?(\mathrm{b})$ Why is 0.1$M \mathrm{CH}_{3} \mathrm{COOH}$ acidic and 0.1$M \mathrm{CH}_{3}$ COONa basic?

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Problem 99

Write balanced equations and $K_{\mathrm{b}}$ expressions for these Bronsted-Lowry bases in water:
(a) Pyridine, $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N} \quad$ (b) $\mathrm{CO}_{3}^{2-}$

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Problem 100

Write balanced equations and $K_{\mathrm{b}}$ expressions for these Bronsted-Lowry bases in water:
(a) Benzoate ion, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COO}^{-} \quad$ (b) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{N}$

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Problem 101

Write balanced equations and $K_{\mathrm{b}}$ expressions for these Bronsted-Lowry bases in water:
(a) Hydroxylamine, $\mathrm{HO}-\mathrm{NH}_{2}$ $\quad$ (b) $\mathrm{HPO}_{4}^{2-}$

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Problem 102

Write balanced equations and $K_{\mathrm{b}}$ expressions for these Bronsted-Lowry bases in water:
(a) Guanidine, $\left(\mathrm{H}_{2} \mathrm{N}\right)_{2} \mathrm{C}=\mathrm{NH}$ (double-bonded $\mathrm{N}$ is most basic $)$
(b) Acetylide ion, $\mathrm{HC} \equiv \mathrm{C}^{-}$

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Problem 103

What is the pH of 0.070$M$ dimethylamine?

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Problem 104

What is the pH of 0.12$M$ diethylamine?

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Problem 105

What is the pH of 0.25$M$ ethanolamine?

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Problem 106

What is the pH of 0.26$M$ aniline?

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Problem 107

(a) What is the $K_{\mathrm{b}}$ of the acetate ion?
(b) What is the $K_{\mathrm{a}}$ of the anilinium ion, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3}^{+} ?$

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Problem 108

(a) What is the $K_{\mathrm{b}}$ of the benzoate ion, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COO}^{-} ?$
(b) What is the $K_{\mathrm{a}}$ of the 2 -hydroxyethylammonium ion,
$\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{3}^{+}\left(\mathrm{p} K_{\mathrm{b}} \text { of } \mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}=4.49\right) ?$

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Problem 109

(a) What is the $\mathrm{p} K_{\mathrm{b}}$ of $\mathrm{ClO}_{2}^{-?}$
(b) What is the $\mathrm{p} K_{\mathrm{a}}$ of the dimethylammonium ion, $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}_{2}^{+} ?$

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Problem 110

(a) What is the $\mathrm{p} K_{\mathrm{b}}$ of $\mathrm{NO}_{2}^{-} ?$
(b) What is the $\mathrm{p} K_{\mathrm{a}}$ of the hydrazinium ion, $\mathrm{H}_{2} \mathrm{N}-\mathrm{NH}_{3}^{+}\left(K_{\mathrm{b}} \text { of }\right.$ hydrazine $=8.5 \times 10^{-7} ) ?$

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Problem 111

(a) What is the pH of 0.150 $M$ $\mathrm{KCN}$ ?
(b) What is the pH of 0.40$M$ triethylammonium chloride, $\left(\mathrm{CH}_{3} \mathrm{CH}_{2}\right)_{3} \mathrm{NHCl}$ ?

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Problem 112

(a) What is the $\mathrm{pH}$ of 0.100 $M$ sodium phenolate, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{ONa},$ the sodium salt of phenol?
(b) What is the $\mathrm{pH}$ of 0.15 $M$ methylammonium bromide, $\mathrm{CH}_{3} \mathrm{NH}_{3} \mathrm{Br}\left(K_{\mathrm{b}} \text { of } \mathrm{CH}_{3} \mathrm{NH}_{2}=4.4 \times 10^{-4}\right) ?$

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Problem 113

(a) What is the pH of 0.65$M$ potassium formate, $\mathrm{HCOOK} ?$
(b) What is the pH of 0.85$M$ $\mathrm{NH}_{4} \mathrm{Br} ?$

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Problem 114

(a) What is the pH of 0.75$M$ $\mathrm{NaF} ?$
(b) What is the pH of 0.88$M$ pyridinium chloride, $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NHCl} ?$

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Problem 115

Sodium hypochlorite solution, sold as chlorine bleach, is potentially dangerous because of the basicity of $\mathrm{ClO}^{-},$ the active bleaching ingredient. What is $\left[\mathrm{OH}^{-}\right]$ in an aqueous solution that is 6.5$\% \mathrm{NaClO}$ by mass? What is the pH of the solution? (Assume that $d$ of the solution is 1.0 $\mathrm{g} / \mathrm{mL}$ .)

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Problem 116

Codeine $\left(\mathrm{C}_{18} \mathrm{H}_{21} \mathrm{NO}_{3}\right)$ is a narcotic pain reliever that forms a salt with $\mathrm{HCl}$. What is the pH of 0.050 $M$ codeine hydrochloride $\left(\mathrm{p} K_{\mathrm{b}} \text { of codeine }=5.80\right) ?$

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Problem 117

What determines whether an aqueous solution of a salt will be acidic, basic, or neutral? Give an example of each type of salt.

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Problem 118

Why is aqueous NaF basic but aqueous NaCl neutral?

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Problem 119

The $\mathrm{NH}_{4}^{+}$ ion forms acidic solutions, and the $\mathrm{CH}_{3} \mathrm{COO}^{-}$ ion forms basic solutions. However, a solution of ammonium acetate is almost neutral. Do all of the ammonium salts of weak acids form neutral solutions? Explain your answer.

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Problem 120

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: $(a)\mathrm{KBr} ;(b) \mathrm{NH}_{4} \mathrm{I} ;(c) \mathrm{KCN}$

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Problem 121

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: (a) $\mathrm{SnCl}_{2};$ (b) $\mathrm{NaHS} ;$ (c) $\mathrm{Zn}\left(\mathrm{CH}_{3} \mathrm{COO}\right)_{2}.$

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Problem 122

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: (a) $\mathrm{Na}_{2} \mathrm{CO}_{3};$ (b) $\mathrm{CaCl}_{2};$ (c) $\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}.$

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Problem 123

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: (a) $\mathrm{CH}_{3} \mathrm{NH}_{3} \mathrm{Cl};$ (b) $\mathrm{LiClO}_{4};$ (c) $\mathrm{CoF}_{2}.$

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Problem 124

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: (a) $\mathrm{SrBr}_{2};$ (b) $\mathrm{Ba}\left(\mathrm{CH}_{3} \mathrm{COO}\right)_{2};$ (c) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}_{2} \mathrm{Br}.$

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Problem 125

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: (a) $\mathrm{Fe}(\mathrm{HCOO})_{3};$ (b) $\mathrm{KHCO}_{3};$ $(\mathrm{c}) \mathrm{K}_{2} \mathrm{S}.$

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Problem 126

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: $(\mathrm{a})\left(\mathrm{NH}_{4}\right)_{3} \mathrm{PO}_{4};$ (b) $\mathrm{Na}_{2} \mathrm{SO}_{4};$ (c) $\mathrm{LiClO}.$

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Problem 127

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: (a) $\mathrm{Pb}\left(\mathrm{CH}_{3} \mathrm{COO}\right)_{2};$ (b) $\mathrm{Cr}\left(\mathrm{NO}_{2}\right)_{3};$ $(\mathrm{c}) \mathrm{CsI}.$

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Problem 128

Rank the following salts in order of increasing pH of their 0.1 $M$ aqueous solutions:
(a) $\mathrm{KNO}_{3}, \mathrm{K}_{2} \mathrm{SO}_{3}, \mathrm{K}_{2} \mathrm{S}, \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2}$
(b) $\mathrm{NH}_{4} \mathrm{NO}_{3}, \mathrm{NaHSO}_{4}, \mathrm{NaHCO}_{3}, \mathrm{Na}_{2} \mathrm{CO}_{3}$

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Problem 129

Rank the following salts in order of decreasing pH of their 0.1$M$ aqueous solutions:
(a) $\mathrm{FeCl}_{2}, \mathrm{FeCl}_{3}, \mathrm{MgCl}_{2}, \mathrm{KClO}_{2}$
(b) $\mathrm{NH}_{4} \mathrm{Br}, \mathrm{NaBrO}_{2}, \mathrm{NaBr}, \mathrm{NaClO}_{2}$

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Problem 130

Methoxide ion, $\mathrm{CH}_{3} \mathrm{O}^{-},$ and amide ion, $\mathrm{NH}_{2}^{-},$ are very strong bases that are “leveled” by water. What does this mean? Write the reactions that occur in the leveling process. What species do the two leveled solutions have in common?

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Problem 131

Explain the differing extents of dissociation of $\mathrm{H}_{2} \mathrm{SO}_{4}$ in $\mathrm{CH}_{3} \mathrm{COOH}, \mathrm{H}_{2} \mathrm{O},$ and $\mathrm{NH}_{3}$ .

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Problem 132

In $\mathrm{H}_{2} \mathrm{O}, \mathrm{HF}$ is weak and the other hydrohalic acids are equally strong. In $\mathrm{NH}_{3},$ however, all the hydrohalic acids are equally strong. Explain.

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Problem 133

What feature must a molecule or ion have in order to act as a Lewis base? A Lewis acid? Explain the roles of these features

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Problem 134

How do Lewis acids differ from Brønsted-Lowry acids? How are they similar? Do Lewis bases differ from Brønsted-Lowry bases? Explain

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Problem 135

(a) Is a weak Bronsted-Lowry base necessarily a weak Lewis base? Explain with an example.
(b) Identify the Lewis bases in the following reaction:
$\mathrm{Cu}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4}^{2+}(a q)+4 \mathrm{CN}^{-}(a q) \rightleftharpoons \mathrm{Cu}(\mathrm{CN})_{4}^{2-}(a q)+4 \mathrm{H}_{2} \mathrm{O}(l)$
(c) Given that $K_{c}>1$ for the reaction in part (b), which Lewis base is stronger?

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Problem 136

In which of the three acid-base concepts can water be a product of an acid-base reaction? In which is it the only product?

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Problem 137

(a) Give an example of a substance that is a base in two of the three acid-base definitions, but not in the third.
(b) Give an example of a substance that is an acid in one of the three acid-base definitions, but not in the other two.

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Problem 138

Which are Lewis acids and which are Lewis bases?
(a) $\mathrm{Cu}^{2+} \quad$ (b) $\mathrm{Cl}^{-} \quad$ (c) $\mathrm{SnCl}_{2} \quad$ (d) $\mathrm{OF}_{2}$

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Problem 139

Which are Lewis acids and which are Lewis bases?
(a) $\mathrm{Na}^{+} \quad$ (b) $\mathrm{NH}_{3} \quad$ (c) $\mathrm{CN}^{-} \quad$ (d) $\mathrm{BF}_{3}$

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Problem 140

Which are Lewis acids and which are Lewis bases?
(a) $\mathrm{BF}_{3} \quad$ (b) $\mathrm{S}^{2-} \quad $ (c) $\mathrm{SO}_{3}^{2-} \quad$ (d) $\mathrm{SO}_{3}$

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Problem 141

Which are Lewis acids and which are Lewis bases?
(a) $\mathrm{Mg}^{2+} \quad$ (b) $\mathrm{OH}^{-} \quad$ (c) $\operatorname{SiF}_{4} \quad$ (d) $\operatorname{BeC} l_{2}$

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Problem 142

Identify the Lewis acid and Lewis base in each reaction:
(a) $\mathrm{Na}^{+}+6 \mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{Na}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{+}$
(b) $\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{2} \mathrm{CO}_{3}$
(c) $\mathrm{F}^{-}+\mathrm{BF}_{3} \rightleftharpoons \mathrm{HF}_{4}^{-}$

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Problem 143

Identify the Lewis acid and Lewis base in each reaction:
(a) $\mathrm{Fe}^{3+}+2 \mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{FeOH}^{2+}+\mathrm{H}_{3} \mathrm{O}^{+}$
(b) $\mathrm{H}_{2} \mathrm{O}+\mathrm{H}^{-} \rightleftharpoons \mathrm{OH}^{-}+\mathrm{H}_{2}$
(c) $4 \mathrm{CO}+\mathrm{Ni} \rightleftharpoons \mathrm{Ni}(\mathrm{CO})_{4}$

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Problem 144

Classify the following as Arrhenius, Bronsted-Lowry, or Lewis acid-base reactions. A reaction may fit all, two, one, or none of the categories:
(a) $\mathrm{Ag}^{+}+2 \mathrm{NH}_{3} \rightleftharpoons \mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}$
(b) $\mathrm{H}_{2} \mathrm{SO}_{4}+\mathrm{NH}_{3} \rightleftharpoons \mathrm{HSO}_{4}^{-}+\mathrm{NH}_{4}^{+}$
(c) $2 \mathrm{HCl} \Longrightarrow \mathrm{H}_{2}+\mathrm{Cl}_{2}$
(d) $\mathrm{AlCl}_{3}+\mathrm{Cl}^{-} \rightleftharpoons \mathrm{AlCl}_{4}^{-}$

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Problem 145

Classify the following as Arrhenius, Bronsted-Lowry, or Lewis acid-base reactions. A reaction may fit all, two, one, or none of the categories:
(a) $\mathrm{Cu}^{2+}+4 \mathrm{Cl}^{-} \rightleftharpoons \mathrm{CuCl}_{4}^{2-}$
(b) Al(OH) $_{3}+3 \mathrm{HNO}_{3} \rightleftharpoons \mathrm{Al}^{3+}+3 \mathrm{H}_{2} \mathrm{O}+3 \mathrm{NO}_{3}^{-}$
(c) $\mathrm{N}_{2}+3 \mathrm{H}_{2} \rightleftharpoons 2 \mathrm{NH}_{3}$
(d) $\mathrm{CN}^{-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{HCN}+\mathrm{OH}^{-}$

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Problem 146

Chloral $\left(\mathrm{Cl}_{3} \mathrm{C}-\mathrm{CH}=\mathrm{O}\right)$ forms a monohydrate, chloral hydrate, the sleep-inducing depressant called “knockout drops” in old movies. (a) Write two possible structures for chloral hydrate, one involving hydrogen bonding and one that is a Lewis adduct. (b) What spectroscopic method could be used to identify the real structure? Explain.

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Problem 147

In humans, blood pH is maintained within a narrow range: acidosis occurs if the blood pH is below 7.35, and alkalosis occurs if the pH is above $7.45 .$ Given that the $\mathrm{p} K_{\mathrm{w}}$ of blood is 13.63 at $37^{\circ} \mathrm{C}$ (body temperature), what is the normal range of $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ and of $\left[\mathrm{OH}^{-}\right]$ in blood?

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Problem 148

The disinfectant phenol, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH},$ has a $\mathrm{p} K_{\mathrm{a}}$ of 10.0 $\mathrm{in}$ water, but 14.4 in methanol.
(a) Why are the values different?
(b) Is methanol a stronger or weaker base than water?
(c) Write the dissociation reaction of phenol in methanol.
(d) Write an expression for the autoionization constant of methanol.

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Problem 149

When carbon dioxide dissolves in water, it undergoes a multi step equilibrium process, with $K_{\text { overall }}=4.5 \times 10^{-7},$ which is simplified to the following:
$$\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{H}_{2} \mathrm{CO}_{3}(a q)$$
$$\mathrm{H}_{2} \mathrm{CO}_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{HCO}_{3}^{-}(a q)+\mathrm{H}_{3} \mathrm{O}^{+}(a q)$$
(a) Classify each step as a Lewis or a Bronsted-Lowry reaction.
(b) What is the pH of non polluted rainwater in equilibrium with clean air $\left(P_{\mathrm{CO}_{2}} \text { in clean air }=4 \times 10^{-4} \mathrm{atm}\right.$ Henry's law constant for $\mathrm{CO}_{2}$ at $25^{\circ} \mathrm{C}$ is 0.033 $\mathrm{mol} / \mathrm{L} \cdot \mathrm{atm} ) ?$
(c) What is $\left[\mathrm{CO}_{3}^{2-}\right]$ in rainwater $\left(K_{\mathrm{a}} \text { of } \mathrm{HCO}_{3}^{-}=4.7 \times 10^{-11}\right) ?$
(d) If the partial pressure of $\mathrm{CO}_{2}$ in clean air doubles in the next few decades, what will the pH of rainwater become?

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Problem 150

Seashells are mostly calcium carbonate, which reacts with $\mathrm{H}_{3} \mathrm{O}^{+}$ according to the equation
$$\mathrm{CaCO}_{3}(s)+\mathrm{H}_{3} \mathrm{O}^{+}(a q) \rightleftharpoons \mathrm{Ca}^{2+}(a q)+\mathrm{HCO}_{3}^{-}(a q)+\mathrm{H}_{2} \mathrm{O}(l)$$
If $K_{w}$ increases at higher pressure, will seashells dissolve more rapidly near the surface of the ocean or at great depths? Explain.

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Problem 151

Many molecules with central atoms from Period 3 or higher take part in Lewis acid-base reactions in which the central atom expands its valence shell. $\mathrm{SnCl}_{4}$ reacts with $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{N}$ as follows:
(a) Identify the Lewis acid and the Lewis base in the reaction.
(b) Give the $nl$ designation of the sublevel of the central atom in the acid before it accepts the lone pair.

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Problem 152

A chemist makes four successive ten-fold dilutions of $1.0 \times 10^{-5} M \mathrm{HCl}$ . Calculate the pH of the original solution and of each diluted solution (through $1.0 \times 10^{-9} \mathrm{M} \mathrm{HCl} )$

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Problem 153

Chlorobenzene, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Cl},$ is a key intermediate in the manufacture of dyes and pesticides. It is made by the chlorination of benzene, catalyzed by $\mathrm{FeCl}_{3},$ in this series of steps:
(1) $\mathrm{Cl}_{2}+\mathrm{FeCl}_{3} \rightleftharpoons \mathrm{FeCl}_{5}\left(\text { or } \mathrm{Cl}^{+} \mathrm{FeCl}_{4}^{-}\right)$
(2) $\mathrm{C}_{6} \mathrm{H}_{6}+\mathrm{Cl}^{+} \mathrm{FeCl}_{4}^{-} \rightleftharpoons \mathrm{C}_{6} \mathrm{H}_{6} \mathrm{Cl}^{+}+\mathrm{FeCl}_{4}^{-}$
(3) $\mathrm{C}_{6} \mathrm{H}_{6} \mathrm{Cl}^{+} \Longrightarrow \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Cl}+\mathrm{H}^{+}$
(4) $\mathrm{H}^{+}+\mathrm{FeCl}_{4}^{-} \rightleftharpoons \mathrm{HCl}+\mathrm{FeCl}_{3}$
(a) Which of the step(s) is (are) Lewis acid-base reactions?
(b) Identify the Lewis acids and bases in each of those steps.

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Problem 154

The beakers shown contain 0.300 L of aqueous solutions of a moderately weak acid HY. Each particle represents 0.010 mol; solvent molecules are omitted for clarity. (a) The reaction in beaker A is at equilibrium. Calculate Q for B, C, and D to determine which, if any, is also at equilibrium. (b) For any not at equilibrium, in which direction does the reaction proceed? (c) Does dilution affect the extent of dissociation of a weak acid? Explain.

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Problem 155

The strength of an acid or base is related to its strength as an electrolyte. (a) Is the electrical conductivity of 0.1$M \mathrm{HCl}$ higher, lower, or the same as that of 0.1$M \mathrm{CH}_{3} \mathrm{COOH}$ ? Explain. (b) Is the electrical conductivity of $1 \times 10^{-7} M \mathrm{HCl}$ higher, lower, or the same as that of $1 \times 10^{-7} \mathrm{M} \mathrm{CH}_{3} \mathrm{COOH}$ ? Explain.

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Problem 156

Esters, $\mathrm{RCOOR}^{\prime}$, are formed by the reaction of carboxylic acids, $\mathrm{RCOOR}^{\prime}$, and alcohols, $\mathrm{R}^{\prime} \mathrm{OH}$, where $\mathrm{R}$ and $\mathrm{R}^{\prime}$ are hydrocarbon groups. Many esters are responsible for the odors of fruit and, thus, have important uses in the food and cosmetics industries. The first two steps in the mechanism of ester formation are

Identify the Lewis acids and Lewis bases in these two steps

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Problem 157

Three beakers contain $100 . \mathrm{mL}$ of $0.10 M$ $\mathrm{HCl}, \mathrm{HClO}_{2},$ and $\mathrm{HClO}$, respectively. (a) Find the pH of each. (b) Describe quantitatively how to make the pH equal in the beakers through the addition of water only.

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Problem 158

Human urine has a normal pH of 6.2. If a person eliminates an average of 1250. mL of urine per day, how many $\mathrm{H}^{+}$ ions are eliminated per week?

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Problem 159

Liquid ammonia autoionizes like water:
$$2 \mathrm{NH}_{3}(l) \longrightarrow \mathrm{NH}_{4}^{+}(a m)+\mathrm{NH}_{2}^{-}(a m)$$
where $(a m)$ represents solvation by $\mathrm{NH}_{3}$ .
(a) Write the ion-product constant expression, $K_{\mathrm{am}} .$
(b) What are the strongest acid and base that can exist in $\mathrm{NH}_{3}(l) ?$
(c) $\mathrm{HNO}_{3}$ and $\mathrm{HCOOH}$ are leveled in $\mathrm{NH}_{3}(l) .$ Explain with equations.
(d) At the boiling point $\left(-33^{\circ} \mathrm{C}\right), K_{\mathrm{am}}=5.1 \times 10^{-27} .$ Calculate $\left[\mathrm{NH}_{4}^{+}\right]$ at this temperature.
(e) Pure sulfuric acid also autoionizes. Write the ion-product constant expression, $K_{\text { sulf }}$ , and find the concentration of the conjugate base at $20^{\circ} \mathrm{C}\left(K_{\text { sulf }}=2.7 \times 10^{-4} \text { at } 20^{\circ} \mathrm{C}\right).$

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Problem 160

Thiamine hydrochloride $\left(\mathrm{C}_{12} \mathrm{H}_{18} \mathrm{ON}_{4} \mathrm{SCl}_{2}\right)$ is a water-soluble form of thiamine (vitamin $\mathrm{B}_{1} ; K_{\mathrm{a}}=3.37 \times 10^{-7} ) .$ How many grams of the hydrochloride must be dissolved in 10.00 $\mathrm{mL}$ of water to give a pH of 3.50$?$

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Problem 161

Tris(hydroxymethyl)aminomethane, known as TRIS or THAM, is a water-soluble base used in synthesizing surfactants and pharmaceuticals, as an emulsifying agent in cosmetics, and in cleaning mixtures for textiles and leather. In biomedical research, solutions of TRIS are used to maintain nearly constant pH for the study of enzymes and other cellular components. Given that the $\mathrm{p} K_{\mathrm{b}}$ is $5.91,$ calculate the $\mathrm{pH}$ of 0.075 $\mathrm{M}$ TRIS.

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Problem 162

When an $\mathrm{Fe}^{3+}$ salt is dissolved in water, the solution becomes acidic due to formation of $\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5} \mathrm{OH}^{2+}$ and $\mathrm{H}_{3} \mathrm{O}^{+}$ . The overall process involves both Lewis and Bronsted-Lowry acid-base reactions. Write the equations for the process.

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Problem 163

What is the pH of a vinegar with 5.0% (w/v) acetic acid in water?

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Problem 164

The scene below represents a sample of a weak acid HB (blue and purple) dissolved in water. Draw a scene that represents the same volume after the solution has been diluted with water

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Problem 165

How would you differentiate between a strong and a weak monoprotic acid from the results of the following procedures? (a) Electrical conductivity of an equimolar solution of each acid is measured. (b) Equal molarities of each are tested with pH paper. (c) Zinc metal is added to solutions of equal concentration.

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Problem 166

The catalytic efficiency of an enzyme is called its activity and refers to the rate at which it catalyzes the reaction. Most enzymes have optimum activity over a relatively narrow pH range, which is related to the pH of the local cellular fluid. The pH profiles of three digestive enzymes are shown.

Salivary amylase begins digestion of starches in the mouth and has optimum activity at a pH of 6.8; pepsin begins protein digestion in the stomach and has optimum activity at a pH of 2.0; and trypsin, released in pancreatic juices, continues protein digestion in the small intestine and has optimum activity at a pH of 9.5. Calculate $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ in the local cellular fluid for each enzyme.

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Problem 167

Acetic acid has a $K_{\mathrm{a}}$ of $1.8 \times 10^{-5},$ and ammonia has a $K_{\mathrm{b}}$ of $1.8 \times 10^{-5} .$ Find $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right],\left[\mathrm{OH}^{-}\right], \mathrm{pH},$ and pOH for (a) 0.240 $\mathrm{M}$ acetic acid and (b) 0.240 $\mathrm{M}$ ammonia.

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Problem 168

The uses of sodium phosphate include clarifying crude sugar, manufacturing paper, removing boiler scale, and washing concrete. What is the pH of a solution containing 33 g of $\mathrm{Na}_{3} \mathrm{PO}_{4}$ per liter? What is $\left[\mathrm{OH}^{-}\right]$ of this solution?

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Problem 169

The Group 5A(15) hydrides react with boron trihalides in a reversible Lewis acid-base reaction. When 0.15 mol of $\mathrm{PH}_{3} \mathrm{BCl}_{3}(s)$ is introduced into a 3.0 $\mathrm{-L}$ container at a certain temperature, $8.4 \times 10^{-3} \mathrm{mol}$ of $\mathrm{PH}_{3}$ is present at equilibrium: $\mathrm{PH}_{3} \mathrm{BCl}_{3}(s) \rightleftharpoons \mathrm{PH}_{3}(g)+\mathrm{BCl}_{3}(g) .$ (a) Find $K_{\mathrm{c}}$ for the reaction at this temperature. $(\mathrm{b})$ Draw a Lewis structure for the reactant.

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Problem 170

A 1.000 m solution of chloroacetic acid $\left(\mathrm{ClCH}_{2} \mathrm{COOH}\right)$ freezes at $-1.93^{\circ} \mathrm{C} .$ Find the $K_{\mathrm{a}}$ of chloroacetic acid. (Assume that the molarities equal the molalities.)

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Problem 171

Sodium stearate $\left(\mathrm{C}_{17} \mathrm{H}_{35} \mathrm{COONa}\right)$ is a major component of bar soap. The $K_{\mathrm{a}}$ of the stearic acid is $1.3 \times 10^{-5} .$ What is the pH of 10.0 $\mathrm{mL}$ of a solution containing 0.42 $\mathrm{g}$ of sodium stearate?

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Problem 172

Calcium propionate $\left[\mathrm{Ca}\left(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COO}\right)_{2} ; \text { calcium propanoate}\right. ]$ is a mold inhibitor used in food, tobacco, and pharmaceuticals. (a) Use balanced equations to show whether aqueous calcium propionate is acidic, basic, or neutral. (b) Use Appendix C to find the resulting $\mathrm{pH}$ when 8.75 $\mathrm{g}$ of $\mathrm{Ca}\left(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COO}\right)_{2}$ dis- solves in enough water to give 0.500 $\mathrm{L}$ of solution.

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Problem 173

A site in Pennsylvania receives a total annual deposition of 2.688 $\mathrm{g} / \mathrm{m}^{2}$ of sulfate from fertilizer and acid rain. The ratio by mass of ammonium sulfate/ammonium bisulfate/sulfuric acid is 3.0/5.5/1.0. (a) How much acid, expressed as kg of sulfuric acid, is deposited over an area of $10 . \mathrm{km}^{2} ?$ (b) How many pounds of $\mathrm{CaCO}_{3}$ are needed to neutralize this acid? (c) If $10 . \mathrm{km}^{2}$ is the area of an unpolluted lake 3 m deep and there is no loss of acid, what pH will the lake water attain by the end of the year? (Assume constant volume.)

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Problem 174

(a) If $K_{\mathrm{w}}=1.139 \times 10^{-15}$ at $0^{\circ} \mathrm{C}$ and $5.474 \times 10^{-14}$ at $50^{\circ} \mathrm{C},$ find $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ and $\mathrm{pH}$ of water at $0^{\circ} \mathrm{C}$ and $50^{\circ} \mathrm{C}.$
(b) The autoionization constant for heavy water (deuterium oxide, $\mathrm{D}_{2} \mathrm{O} )$ is $3.64 \times 10^{-16} \mathrm{at} 0^{\circ} \mathrm{C}$ and $7.89 \times 10^{-15} \mathrm{at} 50^{\circ} \mathrm{C} .$ Find $\left[\mathrm{D}_{3} \mathrm{O}^{+}\right]$ and pD of heavy water at $0^{\circ} \mathrm{C}$ and $50^{\circ} \mathrm{C} .$
(c) Suggest a reason for these differences.

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Problem 175

$\mathrm{HX}(\mathscr{M}=150 . \mathrm{g} / \mathrm{mol})$ and $\mathrm{HY}(\mathscr{M}=50.0 \mathrm{g} / \mathrm{mol})$ are weak acids. A solution of 12.0 g/L of HX has the same pH as one containing 6.00 g/L of HY. Which is the stronger acid? Why?

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Problem 176

The beakers below depict the aqueous dissociations of weak acids HA (blue and green) and HB (blue and yellow); solvent molecules are omitted for clarity. If the HA solution is 0.50 L, and the HB solution is 0.25 L, and each particle represents 0.010 mol, find the $K_{\mathrm{a}}$ of each acid. Which acid, if either, is stronger?

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Problem 177

In his acid-base studies, Arrhenius discovered an important fact involving reactions like the following:
$$\mathrm{KOH}(a q)+\mathrm{HNO}_{3}(a q) \longrightarrow ?$$
$$\mathrm{NaOH}(a q)+\mathrm{HCl}(a q) \longrightarrow ?$$
(a) Complete the reactions and use the data for the individual ions in Appendix $\mathrm{B}$ to calculate each $\Delta H_{\mathrm{rxn}^{\circ}}^{\circ}$
(b) Explain your results and use them to predict $\Delta H_{\mathrm{rxn}}^{\circ}$ for
$$\mathrm{KOH}(a q)+\mathrm{HCl}(a q) \longrightarrow ?$$

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Problem 178

Putrescine $\left[\mathrm{NH}_{2}\left(\mathrm{CH}_{2}\right)_{4} \mathrm{NH}_{2}\right]$ , found in rotting animal tissue, is now known to be in all cells and essential for normal and abnormal (cancerous) growth. It also plays a key role in the formation of GABA, a neurotransmitter. A 0.10$M$ aqueous solution of putrescine has $\left[\mathrm{OH}^{-}\right]=2.1 \times 10^{-3} .$ What is the $K_{\mathrm{b}} ?$

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Problem 179

The molecular scene depicts the relative concentrations of $\mathrm{H}_{3} \mathrm{O}^{+}$ (purple) and $\mathrm{OH}^{-}(\text {green})$ in an aqueous solution at $25^{\circ} \mathrm{C}$ . (Counter ions and solvent molecules are omitted for clarity.) (a) Calculate the pH. (b) How many $\mathrm{H}_{3} \mathrm{O}^{+}$ ions would you have to draw for every $\mathrm{OH}^{-}$ ion to depict a solution of $\mathrm{pH} 4$ ?

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Problem 180

Polymers are not very soluble in water, but their solubility increases if they have charged groups. (a) Casein, a milk protein, contains many $-\mathrm{COO}^{-}$ groups on its side chains. How does the solubility of casein vary with pH? (b) Histones are proteins essential to the function of DNA. They are weakly basic due to the presence of side chains with $-\mathrm{NH}_{2}$ and $=\mathrm{NH}$ groups. How does the solubility of a histone vary with pH?

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Problem 181

Hemoglobin (Hb) transports oxygen in the blood:
$$\mathrm{HbH}^{+}(a q)+\mathrm{O}_{2}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{HbO}_{2}(a q)+\mathrm{H}_{3} \mathrm{O}^{+}(a q)$$
In blood, $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ is held nearly constant at $4 \times 10^{-8} M.$
(a) How does the equilibrium position change in the lungs?
(b) How does it change in $\mathrm{O}_{2}$ -deficient cells?
(c) Excessive vomiting may lead to metabolic alkalosis, in which $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ in blood decreases. How does this condition affect the ability of $\mathrm{Hb}$ to transport $\mathrm{O}_{2} ?$
(d) Diabetes mellitus may lead to metabolic acidosis, in which $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$ in blood increases. How does this condition affect the ability of $\mathrm{Hb}$ to transport $\mathrm{O}_{2} ?$

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Problem 182

Nitrogen is discharged from wastewater treatment facilities into rivers and streams, usually as $\mathrm{NH}_{3}$ and $\mathrm{NH}_{4}^{+} :$
$\mathrm{NH}_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{NH}_{4}^{+}(a q)+\mathrm{OH}^{-}(a q) \quad K_{\mathrm{b}}=1.76 \times 10^{-5}$ One strategy for removing it is to raise the pH and “strip” the $\mathrm{NH}_{3}$ from solution by bubbling air through the water. (a) At pH 7.00 , what fraction of the total nitrogen in solution is $\mathrm{NH}_{3},$ defined as $\left[\mathrm{NH}_{3}\right] /\left(\left[\mathrm{NH}_{3}\right]+\left[\mathrm{NH}_{4}+\right]\right) ?$ (b) What is the fraction at $\mathrm{pH} 10.00 ?(\mathrm{c})$ Explain the basis of ammonia stripping.

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Problem 183

A solution of propanoic acid $\left(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COOH}\right),$ made by dissolving 7.500 g in sufficient water to make 100.0 $\mathrm{mL}$ , has a freezing point of $-1.890^{\circ} \mathrm{C} .$
(a) Calculate the molarity of the solution.
(b) Calculate the molarity of the propanoate ion. (Assume the molarity of the solution equals the molality.)
(c) Calculate the percent dissociation of propanoic acid.

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Problem 184

The antimalarial properties of quinine $\left(\mathrm{C}_{20} \mathrm{H}_{24} \mathrm{N}_{2} \mathrm{O}_{2}\right)$ saved thousands of lives during construction of the Panama Canal. This substance is a classic example of the medicinal wealth of tropical forests. Both N atoms are basic, but the N (colored) of the $3^{\circ}$ amine group is far more basic $\left(\mathrm{p} K_{\mathrm{b}}=5.1\right)$ than the $\mathrm{N}$ within the aromatic ring system ( $\mathrm{p} K_{\mathrm{b}}=9.7 ).$
(a) A saturated solution of quinine in water is only $1.6 \times 10^{-3} M$ . What is the pH of this solution?
(b) Show that the aromatic N contributes negligibly to the ph of the solution.
(c) Because of its low solubility, quinine is given as the salt quinine hydrochloride $\left(\mathrm{C}_{20} \mathrm{H}_{24} \mathrm{N}_{2} \mathrm{O}_{2} \cdot \mathrm{HCl}\right),$ which is 120 times more soluble than quinine. What is the pH of 0.33$M$ quinine hydrochloride?
(d) An antimalarial concentration in water is 1.5$\%$ quinine hydrochloride by mass $(d=1.0 \mathrm{g} / \mathrm{mL}) .$ What is the pH?

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Problem 185

Drinking water is often disinfected with $\mathrm{Cl}_{2},$ which hydrolyzes to form $\mathrm{HClO}$, a weak acid but powerful disinfectant:
$$\mathrm{Cl}_{2}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{HClO}(a q)+\mathrm{H}_{3} \mathrm{O}^{+}(a q)+\mathrm{Cl}^{-}(a q)$$
The fraction of HClO in solution is defined as
$$\frac{\lfloor\mathrm{HClO}]}{[\mathrm{HClO}]+\left[\mathrm{ClO}^{-}\right]}$$
(a) What is the fraction of HClO at pH 7.00$\left(K_{\mathrm{a}} \text { of } \mathrm{HClO}=\right.$
$2.9 \times 10^{-8} ) ?$ (b) What is the fraction at pH 10.00$?$

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Problem 186

The following scenes represent three weak acids $\mathrm{HA}$ (where $\mathrm{A}=\mathrm{X}, \mathrm{Y},$ or $\mathrm{Z}$ ) dissolved in water $\left(\mathrm{H}_{2} \mathrm{O} \text { is not shown): }\right.$

(a) Rank the acids in order of increasing $K_{\mathrm{a}} \cdot(\mathrm{b})$ Rank the acids in order of increasing $\mathrm{p} K_{\mathrm{a}},(\mathrm{c})$ Rank the conjugate bases in order of increasing $\mathrm{p} K_{\mathrm{b}}$ . (d) What is the percent dissociation of $\mathrm{HX} ?(\mathrm{e})$ If equimolar amounts of the sodium salts of the acids ($\mathrm{NaX}, \mathrm{NaY}$, and $\mathrm{NaZ}$ ) were dissolved in water, which solution would have the highest pOH? The lowest pH?

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