Question

Part A

A student measures the OH- concentration in a saturated aqueous solution of nickel(II) hydroxide to be 8.44×10-6 M. Based on her data, the solubility product constant for nickel(II) hydroxide is

Part B

A student measures the Pb²⁺ concentration in a saturated aqueous solution of lead bromide to be 1.14×10^-2 M.
Based on her data, the solubility product constant for lead bromide is

Part C

A student measures the molar solubility of silver carbonate in a water solution to be 1.29×10^-4 M.
Based on her data, the solubility product constant for this compound is

Answer 1

Part A)

Ni(OH)2 solubilizes as

Ni(OH)₂ $\rightleftharpoons$ Ni²⁺(aq) + 2 OH^-(aq)

                    x              2x

Since OH^- is 8.44×10^-6 M Ni²⁺ will be 8.44×10^-6 M/2 = 4.22 ×10^-6 M

Ksp = [Ni²⁺][OH^-]²

Ksp = 4.22 ×10^-6 x (8.44×10^-6)²

Ksp = 3.00 x 10^-16

Part B

A student measures the Pb²⁺ concentration in a saturated aqueous solution of lead bromide to be 1.14×10^-2 M.

PbBr₂ $\rightleftharpoons$ Pb²⁺(aq) + 2 ^Br-(aq)

                    x              2x

Since Pb²⁺ is 1.14×10^-2 M Br^- is 1.14×10^-2 M x 2 = 2.28 ×10^-2 M

Ksp = [Pb²⁺][Br^-]²

Ksp = 1.14×10^-2 x (2.28 ×10^-2)²

Ksp = 5.92 x 10^-6

Part C

A student measures the molar solubility of silver carbonate in a water solution to be 1.29×10^-4 M.

Ag₂CO₃ $\rightleftharpoons$ 2Ag⁺ (aq) + CO₃^2-(aq)

molar solubility is 1.29×10^-4 M so silver ions are 2 x 1.29×10^-4 M = 2.58 ×10^-4 M

Ksp = [Ag⁺]²[CO₃^2-]

= (2.58 ×10^-4)² (1.29×10^-4)

Ksp = 8.58 x 10^-12