Question

Calculate the solubility at 25°C of NiOH2 in pure water and in a 0.0150M NaOH solution. You'll find Ksp data in the ALEKS Data tab. Round both of your answers to 2 significant digits.

Calculate the solubility at 25 °C of Ni(OH), in pure water and in a 0.0150 M NaOH solution. You'll find K, data in the ALEKS Data tab. Round both of your answers to 2 significant digits. solubility in pure water: 60 - solubility in 0.0150 M NaOH solution: 60 - x s ?

Answer 1

Ksp of 2*10^-15

Ni(OH)2(s) --------------> Ni^2+ (aq) + 2OH^- (aq)

                                         s                  2s

Ksp   = [Ni^2+][OH^-]^2

2*10^-15   = s*(2s)^2

s   = 7.94*10^-6

solubility of Ni(OH)2   = 7.94*10^-6 moles/L >>>>>answer

molar mass of Ni(OH)2   = 92.708g/mole

solubility of Ni(OH)2   = 7.94*10^-6 *92.708   = 7.4*10^-4g/L >>>>>answer

Ksp   = [Ni^2+][OH^-]^2

NaOH(aq) --------------> Na^+ (aq) + OH^- (aq)

0.015M                                                  0.015M

Ni(OH)2(s) --------------> Ni^2+ (aq) + 2OH^- (aq)

                                         s                  2s+0.015

Ksp   = [Ni^2+][OH^-]^2

2*10^-15 = s*(2s+0.015)^2

2*10^-15 = s*(2s+0.015)^2          [ 2s+0.015 = 0.015 , 2s<<<<0.015]

2*10^-15 = s*(0.015)^2

s   = 8.8*10^-12

solublity of Ni(OH)2 = 8.8*10^-12mole/L >>>>>answer

molar mass of Ni(OH)2   = 92.708g/mole

solublity of Ni(OH)2 = 8.8*10^-12*92.708   = 8.2*10^-10g/L >>>>answer