Question

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

• A. Cationic part
• B. Anionic part
• C. Both in the cationic and anionic parts
• D. Precipitate

Answer 1

The correct option is B Anionic part

The reaction occurs is:
$2NaOH+Z{n}^{2+}\to \underset{\text{(white ppt.)}}{Zn(OH{)}_2}\downarrow +2N{a}^{+}$

$\underset{\text{(white ppt.)}}{Zn(OH{)}_2}+2NaOH\to N{a}_2\left[Zn\right(OH{)}_4]$

From the above reaction, it can be seen that zinc exists in the anionic part.