Paragraph: When potassium iodide is added to an aqueous solution of potassium ferricyanide, a reversible…
Paragraph: When potassium iodide is added to an aqueous solution of potassium ferricyanide, a reversible reaction is observed in which a complex \(\mathrm{P}\) is formed. In a strong acidic medium, the equilibrium shifts completely towards \(\mathrm{P}\). Addition of zinc chloride to \(\mathrm{P}\) in a slightly acidic medium results in a sparingly soluble complex Q.
Question: The number of moles of potassium iodide required to produce two moles of $\mathbf{P}$ is
Solution
$\mathrm{KI}+\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_6\right] \rightleftharpoons \mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]+\frac{1}{2} \mathrm{I}_2$
Moles of $\mathrm{KI}$ required $=2$