Question

1) The solubility of Ni(OH)₂ is measured and found to be 3.90×10^-4 g/L. Use this information to calculate a K_sp value for nickel(II) hydroxide.

K_sp = _______

2) The solubility of Ag₂CO₃ is measured and found to be 3.58×10^-2 g/L. Use this information to calculate a K_sp value for silver carbonate.

K_sp = _________

3) The mass of silver phosphate that is dissolved in 250 mL of a saturated solution is _____grams.

4)The mass of silver bromide that is dissolved in 250 mL of a saturated solution is ______grams.

5) A solution contains 0.348 M ammonium bromide and 0.463 M ammonia.

The pH of this solution is _____ .

6) A solution contains 0.180 M ammonium bromide and 9.98×10^-2 M ammonia.

The pH of this solution is ________

Answer 1

Let us consider a reaction,

Ni(OH)2 (s) ---->  Ni2+ + 2OH-

molar S = Solubility / MW

= (3.9*10^-4) / 92.708

= 0.00000420675 M

Let us consider a reaction,

Ni(OH)2 -----> Ni+2 + 2OH-

K_sp = [Ni+2][OH-]^2

K_sp = (0.00000420675) x (2*0.00000420675)²

K_sp = 2.97 *10^-16