What is the minimum p H required to prevent the precipitation of Z n S in a solution that is 0.01 M Z n C l 2 and saturated with 0.10 M H 2 S ? [Given K s p = 10 – 21 , K a 1 × K a 2 = 10 – 20 ]

Step-by-step solution

K s p = [ Z n 2 + ] [ S 2 – ] [ S 2 – ] = 1 0 – 21 0.01 = 10 – 19 for K a 1 . K a 2 = [ H + ] 2 [ S 2 – ] [ H 2 S ] 10 – 20 = [ H + ] 2 × 1 0 – 19 0.1 ⇒ [ H + ] = 0.1 or p H = 1