Question

Use the References to access important values if needed for this question, A student measures the s concentration in a saturated aqueous solution of nickel() sulfide to be 5.33x10-11 M Based on her data, the solubility product constant for nickel(II) sulfide is Submit Answer Retry Entire Group 7 more group attempts remaining

Answer 1

NiS     =     Ni²⁺     +     S^2-

Ksp = [Ni²⁺] [S^2-]

Here [S^2-] = 5.33 x 10^-11 M = [Ni²⁺]

So,

Ksp = (5.33 x 10^-11) (5.33 x 10^-11) = 2.84 x 10^-21

Cr(OH)3     =     Cr³⁺     +     3OH^-

Ksp = [Cr³⁺] [OH^-]³

Here [Cr³⁺] = 1.24 x 10^-8 M

So, [OH^-] = 3 (1.24 x 10^-8) = 3.72 x 10^-8 M

Ksp = (1.24 x 10^-8) (3.72 x 10^-8)³
       = (1.24 x 10^-8) (5.15 x 10^-23)
      = 6.39 x 10^-31

The solubility of Cr(OH)3 is 1.27 x 10^-6 g/L

Molar mass of Cr(OH)3 = 103 g /mol

So, 103 g of Cr(OH)3 = 1 mol

1 g of Cr(OH)3 = (1/103) mol

(1.27 x 10^-6) g of Cr(OH)3 = [ (1.27 x 10^-6) / 103 ] mol
                                           = 1.23 x 10^-8 mol

So, the solubility of Cr(OH)3 is 1.27 x 10^-6 g/L = 1.23 x 10^-8 mol/L
                                                                            = 1.23 x 10^-8 M

Now,

Cr(OH)3     =     Cr³⁺     +     3OH^-

Ksp = [Cr³⁺] [OH^-]³

Here [Cr³⁺] = 1.23 x 10^-8 M

So, [OH^-] = 3 (1.23 x 10^-8) = 3.69 x 10^-8 M

Ksp = (1.23 x 10^-8) (3.69 x 10^-8)³
       = (1.24 x 10^-8) (5.02 x 10^-23)
      = 6.22 x 10^-31

The solubility of Ag2CrO4 is 4.23 x 10^-2 g/L

Molar mass of Ag2CrO4 = 332 g /mol

So, 332 g of Ag2CrO4 = 1 mol

1 g of Ag2CrO4 = (1/332) mol

(4.23 x 10^-2) g of Ag2CrO4 = [ (4.23 x 10^-2) / 332 ] mol
                                            = 1.27 x 10^-4 mol

So, the solubility of Ag2CrO4 is 4.23 x 10^-2 g/L = 1.27 x 10^-4 mol/L
                                                                             = 1.27 x 10^-4 M

Now,

Ag2CrO4     =     2Ag⁺     +     CrO4^-2

Ksp = [Ag⁺]² [CrO4^-2]

Here [Ag⁺] = 2 x (1.27 x 10^-4) M = 2.54 x 10^-4 M

So, [CrO4^-2] = 1.27 x 10^-4 M

Ksp = (2.54 x 10^-4)² (1.27 x 10^-4)
       = (6.45 x 10^-8) (1.27 x 10^-4)
      = 8.19 x 10^-12