Question

When potassium iodide is added to an aqueous solution of potassium ferricyanide, a reversible reaction is observed in which a complex P is formed. In a strong acidic medium, the equilibrium shifts completely towards P. Addition of zinc chloride to P in a slightly acidic medium results in a sparingly soluble complex Q.

(1) The number of moles of potassium iodide required to produce two moles of P is ______.

(2) The number of zinc ions present in the molecular formula of Q is _____.

Answer 1

(1) 2

\(KI + K_3 [Fe(CN)_6] \rightleftharpoons K_4 [Fe(CN)_6] + \frac12I_2\)

Moles of KI required = 2

(2) 3 or 2

\(Zn^{2+} + K_4[Fe(CN)_6] \to K_2Zn_3 [Fe(CN)_6]_2\)

OR

\(Zn^{2+} + K_4[Fe(CN)_6] \to Zn_2 [Fe(CN)_6]\)