A solution when diluted with `H_(2)O` and boiled, it gives a white precipitate. On addition of excess `NH_(4)Cl//NH_(4)OH` the volume of precipitate decreases leaving behind a white gelatinous precipitate. Identify the precipitate which dissolves in `NH_(4)OH//NH_(4)Cl`

Options

A. `Zn(OH)_(2)`
B. `AI(OH)_(3)`
C. `Mg(OH)_(2)`
D. `Ca(OH)_(2)`

Answer

A

Explanation

Due to formation of tetra-ammine zinc (II) complex, `Zn^(2+) + NH_(4) OH to [Zn(NH_(3))_(4)]^(+2)`