The dissociation constants for acetic acid and HCN at 25^ C are 1.5 10⁻⁵ and 4.5 10⁻¹⁰ , respectively. The equilibrium constant for the equilibrium, CN ⁻+ CH ₃ COOH HCN + CH ₃ COO ⁻ would be

Step-by-step solution

Given, CH ₃ COOH CH ₃ COO ⁻+ H ⁺ array r K _ a =1.5 10⁻⁵ (i) HCN H ⁺+ CN ⁻ ; K _ a =4.5 10⁻¹⁰ (ii) CN ⁻+ CH ₃ COOH HCN + CH ₃ COO ⁻ K = ? array On substracting Eq. (ii) from Eq. (i), we get aligned & CH ₃ COOH + CN ⁻ HCN + CH ₃ COO ⁻ ; & K = K _ a K _ a ₁ = 1.5 10⁻⁵ 4.5 10⁻¹⁰ = 10^5 3 =3.33 10^4 aligned While adding two equations, dissociation constants are multiplied and when subtracting the equations, dissociation constants are divided. Alternative aligned & CH ₃ COOH CH ₃ COO ⁻+ H ⁺ ; K _ a =1.5 10⁻⁵ & ~K _ a =