Q: If the $K_{sp}$ of $\mathrm{AgCl}$ is $1.8 \times 10^{-10}$ at $25^\circ$C, what is the molar solubility of $\mathrm{AgCl}$ in pure water?

$1.3 \times 10^{-5}\ \mathrm{mol/L}$

Q: A student adds enough $\mathrm{NaF}$ to a saturated solution of $\mathrm{CaF_2}$ to make $[\mathrm{F^-}] = 0.10\ \mathrm{M}$. If $K_{sp}$ for $\mathrm{CaF_2}$ is $4.0 \times 10^{-11}$, what is the new equilibrium concentration of $\mathrm{Ca^{2+}}$?

$4.0 \times 10^{-9}\ \mathrm{M}$

Q: The $K_{sp}$ for $\mathrm{PbSO_4}$ is $6.3 \times 10^{-7}$ at $25^\circ$C. If $[\mathrm{SO_4^{2-}}]$ is increased to $1.0\ \mathrm{M}$ by adding $\mathrm{MgSO_4}$, what is the equilibrium concentration of $\mathrm{Pb^{2+}}$?

$6.3 \times 10^{-7}\ \mathrm{M}$

Q: For the dissolution of $\mathrm{Ca_3(PO_4)_2}$: $\mathrm{Ca_3(PO_4)_2(s) \rightleftharpoons 3Ca^{2+}(aq) + 2PO_4^{3-}(aq)}$, if $K_{sp} = 1.0 \times 10^{-25}$, what is the molar solubility $s$?

$s = (1.0 \times 10^{-25}/108)^{1/5}$

Question 1

Which of the following statements best describes a saturated solution at equilibrium for an ionic solid in water?

Accepted Answer

No more solid can dissolve, and the rates of dissolution and precipitation are equal.

Question 2

Given the dissolution reaction $\mathrm{CaF_2(s) \rightleftharpoons Ca^{2+}(aq) + 2F^-(aq)}$, which is the correct expression for the solubility product constant $K_{sp}$?

Accepted Answer

$K_{sp} = [\mathrm{Ca^{2+}}][\mathrm{F^-}]^2$

Question 3

If the $K_{sp}$ of $\mathrm{AgCl}$ is $1.8 	imes 10^{-10}$ at $25^\circ$C, what is the molar solubility of $\mathrm{AgCl}$ in pure water?

Accepted Answer

$1.3 	imes 10^{-5}\ \mathrm{mol/L}$

Question 4

Which of the following will decrease the solubility of $\mathrm{AgCl}$ in water?

Accepted Answer

Adding $\mathrm{NaCl}$ to the solution

Question 5

A student adds enough $\mathrm{NaF}$ to a saturated solution of $\mathrm{CaF_2}$ to make $[\mathrm{F^-}] = 0.10\ \mathrm{M}$. If $K_{sp}$ for $\mathrm{CaF_2}$ is $4.0 	imes 10^{-11}$, what is the new equilibrium concentration of $\mathrm{Ca^{2+}}$?

Accepted Answer

$4.0 	imes 10^{-9}\ \mathrm{M}$

Question 6

Which of the following compounds will have the highest molar solubility in water, given their $K_{sp}$ values? $\mathrm{AgCl}$ ($K_{sp} = 1.8 	imes 10^{-10}$), $\mathrm{AgBr}$ ($K_{sp} = 5.0 	imes 10^{-13}$), $\mathrm{AgI}$ ($K_{sp} = 8.3 	imes 10^{-17}$)

Accepted Answer

$\mathrm{AgCl}$

Question 7

The $K_{sp}$ for $\mathrm{PbSO_4}$ is $6.3 	imes 10^{-7}$ at $25^\circ$C. If $[\mathrm{SO_4^{2-}}]$ is increased to $1.0\ \mathrm{M}$ by adding $\mathrm{MgSO_4}$, what is the equilibrium concentration of $\mathrm{Pb^{2+}}$?

Accepted Answer

$6.3 	imes 10^{-7}\ \mathrm{M}$

Question 8

Which of the following best explains the common ion effect?

Accepted Answer

The solubility of a salt decreases when a solution already contains one of its ions.

Question 9

For the dissolution of $\mathrm{Ca_3(PO_4)_2}$: $\mathrm{Ca_3(PO_4)_2(s) ightleftharpoons 3Ca^{2+}(aq) + 2PO_4^{3-}(aq)}$, if $K_{sp} = 1.0 	imes 10^{-25}$, what is the molar solubility $s$?

Accepted Answer

$s = (1.0 	imes 10^{-25}/108)^{1/5}$

Question 10

A saturated solution of $\mathrm{BaSO_4}$ is prepared. Which of the following will NOT appear in the equilibrium expression for $K_{sp}$?

Accepted Answer

$[\mathrm{BaSO_4(s)}]$

Question 11

Which of the following changes will increase the solubility of $\mathrm{Mg(OH)_2}$ in water?

Accepted Answer

Decreasing the pH of the solution

Question 12

If $K_{sp}$ for $\mathrm{Ag_2CO_3}$ is $8.1 	imes 10^{-12}$, what is the molar solubility $s$ of $\mathrm{Ag_2CO_3}$?

Accepted Answer

$s = (K_{sp}/4)^{1/3}$

Question 13

A solution contains $[\mathrm{Ag^+}] = 1.0 	imes 10^{-5}\ \mathrm{M}$ and $[\mathrm{Cl^-}] = 1.0 	imes 10^{-5}\ \mathrm{M}$. If $K_{sp}$ for $\mathrm{AgCl}$ is $1.8 	imes 10^{-10}$, what will happen?

Accepted Answer

The solution is saturated and no change will occur.

Question 14

Which of the following best describes the difference between solubility and $K_{sp}$?

Accepted Answer

Solubility is the amount that dissolves (g/L or mol/L), while $K_{sp}$ is the equilibrium constant for the dissolution reaction.

Question 15

Which of the following factors does NOT affect the value of $K_{sp}$ for a given salt?

Accepted Answer

The presence of a common ion

Question 16

A patient is treated for lead poisoning. To reduce $\mathrm{Pb^{2+}}$ in the blood, a doctor administers a solution containing $\mathrm{SO_4^{2-}}$. What is the chemical principle behind this treatment?

Accepted Answer

The addition of $\mathrm{SO_4^{2-}}$ causes $\mathrm{PbSO_4}$ to precipitate, lowering $\mathrm{Pb^{2+}}$ concentration via the common ion effect.

Question 17

Which of the following is true about the dissolution of $\mathrm{BaSO_4}$ in water?

Accepted Answer

At equilibrium, the rate of dissolution equals the rate of precipitation.

Question 18

A chemist wants to increase the solubility of $\mathrm{Fe(OH)_3}$ in water. Which of the following would be most effective?

Accepted Answer

Adding acid to lower the pH

Solubility Equilibria and the Solubility Product Constant ($K_{sp}$)

Study Guide - Practice Questions

Study Guide - Flashcards