Q: Predict the pH ($>7$, $=7$, or $<7$) of the following solutions: NaBr, KNO$_3$, NaNO$_2$, CO(NH$_2$)$_2$.

NaBr: 7, KNO$_3$: 7, NaNO$_2$: >7, CO(NH$_2$)$_2$: <7

Question 1

Which of the following is the correct equilibrium expression for the reaction: $\mathrm{PO_4^{3-} (aq) + H_2O (l) \rightleftharpoons HPO_4^{2-} (aq) + OH^- (aq)}$?

Accepted Answer

$K = \dfrac{[HPO_4^{2-}][OH^-]}{[PO_4^{3-}]}$

Question 2

Which statement is true regarding the reaction: $\mathrm{CH_3COOH (aq) + CT^- (aq) \rightarrow CH_3COO^- (aq) + CH_3COOH_2^+ (aq)}$?

Accepted Answer

The reaction favors the formation of CH$_3$COOH$_2^+$.

Question 3

Which of the following indicates the most basic solution?

Accepted Answer

$[OH^-] = 1 	imes 10^{-2}$ M

Question 4

The pH of a $1 	imes 10^{-11}$ M HCl solution will be:

Accepted Answer

7

Question 5

Acetic acid, CH$_3$COOH, is a weak acid ($K_a = 1.8 	imes 10^{-5}$). Calculate the pH of a 4.6 M HCl/CH$_3$COOH solution.

Accepted Answer

pH = 0.34

Question 6

A solution is made with $[NH_3] = 0.1$ M and $[NH_4^+] = 0.1$ M. What is the pH if $K_b = 1.8 	imes 10^{-5}$?

Accepted Answer

pH = 9.25

Question 7

Which of the following is the correct expression for the concentration of a weak acid in its conjugate acid/base pair?

Accepted Answer

$\mathrm{pH = pK_a + \log \left(\dfrac{[A^-]}{[HA]}\right)}$

Question 8

Which of the following is NOT a buffer solution?

Accepted Answer

HCl and NaCl

Question 9

Predict the pH ($>7$, $=7$, or $<7$) of the following solutions: NaBr, KNO$_3$, NaNO$_2$, CO(NH$_2$)$_2$.

Accepted Answer

NaBr: 7, KNO$_3$: 7, NaNO$_2$: >7, CO(NH$_2$)$_2$: <7

Question 10

Which of the following is a Lewis acid?

Accepted Answer

Al$^{3+}$

Question 11

A solution contains 0.20 M NaCl and 0.30 M NaOH. Its pH is:

Accepted Answer

13.48

Question 12

The pH of 1.00 L of buffer containing 1.00 M CH$_3$COOH and 1.00 M CH$_3$COONa after addition of 0.01 mol NaOH is:

Accepted Answer

4.79

Question 13

Methyl orange is an indicator with a $K_a$ of $1 	imes 10^{-4}$. In acid form, HIn is red, while in base form, In$^-$ is yellow. At pH 4.0, the indicator will be:

Accepted Answer

A mixture of red and yellow

Question 14

If you titrate 0.100 M hydrochloric acid (HCl) with 0.08 M NaOH at 25$^\circ$C, the solution at the equivalence point will be:

Accepted Answer

Slightly acidic

Question 15

In a titration experiment, 25.0 mL of 0.500 M NaOH neutralized 40.0 mL of HCl. The concentration of HCl is:

Accepted Answer

0.313 M

Question 16

Exactly 100.0 mL of 0.100 M HNO$_3$ are titrated with 0.100 M NaOH solution. What is the pH at the equivalence point?

Accepted Answer

7.00

Question 17

The correct mathematical expression for finding the molar solubility ($s$) of Sr(OH)$_2$ is:

Accepted Answer

$K_{sp} = 4s^3$

Question 18

The molar solubility of silver phosphate, Ag$_3$PO$_4$, is $1.6 	imes 10^{-5}$ mol/L. Its solubility product $K_{sp}$ is:

Accepted Answer

$1.57 	imes 10^{-18}$

Question 19

The molar solubility for CaF$_2$ in water at 25$^\circ$C is $2.1 	imes 10^{-4}$ M. What is its $K_{sp}$?

Accepted Answer

$1.85 	imes 10^{-11}$

Question 20

The molar solubility of Fe(OH)$_3$ ($K_{sp} = 1.6 	imes 10^{-39}$) at pH 8.00 is:

Accepted Answer

$1.6 	imes 10^{-21}$ M

Acid-Base Equilibria and Solubility: Practice Exam Study Notes (Chapters 16-17)

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