Question

The molar solubility of ag2s is 1.26 × 10-16 m in pure water. calculate the ksp for ag2s.

Answer 1

Answer is: Ksp for silver sulfide is 8.00·10⁻⁴⁸.
Reaction of dissociation: Ag₂S(s) → 2Ag⁺(aq) + S²⁻(aq).
s(Ag₂S) = s(S²⁻) = 1.26·10⁻¹⁶ M.
s(Ag⁺) = 2s(Ag₂S) = 2.52·10⁻¹⁶ M; equilibrium concentration of silver cations.
Ksp = s(Ag⁺)² · s(S²⁻).
Ksp = (2.52·10⁻¹⁶ M)² · 1.26·10⁻¹⁶ M.
Ksp = 6.35·10⁻³² M² · 1.26·10⁻¹⁶ M.
Ksp = 8.00·10⁻⁴⁸ M³.