Zn(CN)2 ==> Zn^2+ + 2CN^-
.....................+
.....................H^+
.....................v
.....................v
.....................HCN
Note that the added H^+ form HCN with the anion and that forces the solubility equilibrium t the right which increases the solubility of the salt.
Ksp = (Zn^+)(CN^-)^2
So let S = solubility Zn(CN)2 which makes Zn = S and CN^- = 2S*X where X is the fraction of HCN in the form of CN^-
X = Ka/(H^+ + Ka)
From pH you get X, 2S*X gives you CN, 100-X gives you fraction in HCN and you solve the Ksp equation to give you Zn^2+
Determine [Zn2 ], [CN–], and [HCN] in a saturated solution of Zn(CN)2 with a fixed pH of 2.640. The Ksp for Zn(CN)2 is 3.0 × 10–16. The Ka for HCN is 6.2 × 10–10.
I need to know what equations to use to find the answer not just how to get it
1 answer