Q: Given the $$K_{sp}$$ for AgCl is $$1.77 \times 10$$^{-10}$$, what is the molar solubility (S$) of AgCl in pure water?

$$S = \sqrt{1.77 \times 10$$^{-10}$$} = 1.33 \times 10$$^{-5}$$ M

Q: Calculate the molar solubility ($$S) of $$PbCl$$_2 in $$pure water if $$K_{sp} = 1.17 \times 10$$^{-5}$$. Use the formula K$$_{sp} = $$4S^3.$$

$$S = \sqrt[3]{\frac{K_{sp}}{4}} = 1.43 \times 10$$^{-2}$$ M

Question 1

A plumber finds a pipe clogged with a greenish mineral deposit, as shown in the image. The deposit is primarily composed of CaCO$$_3. $$Which environmental factor would most likely increase the rate at which CaCO$$_3$$ dissolves and thus reduce clogging?

Accepted Answer

Decreasing the pH of the water (making it more acidic)

Question 2

Which of the following correctly describes the solubility product constant ($$K_{sp}) $$for AgCl?

Accepted Answer

$$K_{sp} = [Ag^+][Cl^-]$$

Question 3

Given the $$K_{sp}$$ for AgCl is $$1.77 	imes 10$$^{-10}$$, what is the molar solubility (S$) of AgCl in pure water?

Accepted Answer

$$S = \sqrt{1.77 	imes 10$$^{-10}$$} = 1.33 	imes 10$$^{-5}$$ M

Question 4

A student compares the $$K_{sp}$$ values of CaF$$_2$$ and MgCO$$_3$$ and concludes that CaF$$_2 is $$less soluble because its $$K_{sp} is $$smaller. Why is this reasoning flawed?

Accepted Answer

Because $$K_{sp}$$ values can only be compared directly for compounds with the same stoichiometry

Question 5

What is the correct $$K_{sp}$$ expression for PbCl$$_2$$?

Accepted Answer

$$K_{sp} = [Pb$$^{2+}$$][Cl^-]^2$$

Question 6

Calculate the molar solubility ($$S) of $$PbCl$$_2 in $$pure water if $$K_{sp} = 1.17 	imes 10$$^{-5}$$. Use the formula K$$_{sp} = $$4S^3.$$

Accepted Answer

$$S = \sqrt[3]{\frac{K_{sp}}{4}} = 1.43 	imes 10$$^{-2}$$ M

Question 7

Which scenario best illustrates the common ion effect?

Accepted Answer

Adding NaCl to a saturated AgCl solution decreases AgCl solubility

Question 8

If CaF$$_2 is $$dissolved in a solution containing 0.100 M NaF, what is the initial concentration of the common ion?

Accepted Answer

0.100 M F$$^-$$

Question 9

Which of the following compounds will have increased solubility in acidic conditions?

Accepted Answer

BaF$$_2$$

Question 10

A cave formation (stalactite/stalagmite) is primarily composed of CaCO$$_3. $$Which chemical reaction explains its dissolution in acidic rainwater?

Accepted Answer

$$CaCO_3(s) + 2H$$^+ \rightarrow $$Ca^{2+} + H_2O$$ + $$CO_2$$

Question 11

Which anion would NOT be affected by pH changes in terms of solubility?

Accepted Answer

Cl$$^-$$

Question 12

What is the effect of adding Ca(NO$$_3$$)$$_2 to a $$saturated solution of CaF$$_2$$?

Accepted Answer

The solubility of CaF$$_2$$ decreases due to the common ion effect

Question 13

Which equation correctly relates the molar solubility ($$S) of Ag$_2SO$_4 to $$its $$K_{sp}$$?

Accepted Answer

$$K_{sp} = 4S^2$

Question 14

Which of the following statements about saturated solutions is correct?

Accepted Answer

The ion concentrations are at equilibrium and Q = K$$_{sp}$$

Question 15

A solution contains both CaF$$_2$$ and NaF. What happens to the solubility of CaF$$_2$$ compared to pure water?

Accepted Answer

It decreases due to the common ion effect

Question 16

Which compound's solubility would NOT increase in acidic conditions?

Accepted Answer

AgCl

Question 17

If the $$K_{sp} of Fe(OH$$)$$_2 is$$ $$4.87 	imes 10$$^{-17}$$, what is its molar solubility (S$) in pure water?

Accepted Answer

$$S = \sqrt[3]{\frac{K_{sp}}{4}} = 2.30 	imes 10$$^{-6}$$ M

Question 18

Which of the following is TRUE about the solubility product constant ($$K_{sp}$$)?

Accepted Answer

$$K_{sp} is $$always much less than 1 for sparingly soluble compounds

Solubility Product Constant (Ksp), Molar Solubility, and the Common Ion Effect

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