If NaOH is added to an aqueous solution of zinc ions, a white precipitate appears and on adding excess of NaOH, the precipitate dissolves. In this solution, zinc exists in the:

Anionic part

When NaOH is added to an aqueous solution of zinc ions, a white precipitate appears. This white precipitate is zinc hydroxide (\(Zn(OH)_2\)), which is insoluble in water.

When excess NaOH is added, the precipitate dissolves. This is because zinc hydroxide reacts with excess hydroxide ions (\(OH^-\)) from NaOH to form a soluble complex, known as sodium zincate:

\[Zn(OH)_2 + 2 OH^- \rightarrow [Zn(OH)_4]^{2-}\]

In this solution, zinc exists in the anionic part as \([Zn(OH)_4]^{2-}\). Therefore, the correct answer is (1) Anionic part.