When a small amount of KOH solution is added to an aqueous solution of ZnSO₄, a white precipitate of zinc hydroxide is formed. However, when excess KOH is added, the precipitate dissolves to form a soluble complex, potassium zincate. The chemical equations are as follows: 1. Formation of white precipitate: $$ \begin{aligned} \text{ZnSO}_4(aq) + 2\text{KOH}(aq) &\rightarrow \text{Zn(OH)}_2(s) \downarrow + \text{K}_2\text{SO}_4(aq) \end{aligned} $$ 2. Dissolution of precipitate in excess KOH: $$ \begin{aligned} \text{Zn(OH)}_2(s) + 2\text{KOH}(aq) &\rightarrow \text{K}_2\text{ZnO}_2(aq) + 2\text{H}_2\text{O}(l) \end{aligned} $$ Overall reaction with excess KOH: $$ \begin{aligned} \text{ZnSO}_4(aq) + 4\text{KOH}(aq) &\rightarrow \text{K}_2\text{ZnO}_2(aq) + \text{K}_2\text{SO}_4(aq) + 2\text{H}_2\text{O}(l) \end{aligned} $$ Here, K₂ZnO₂ is potassium zincate.