Question

The reagents, $N{H}_{4}Cl$ and aqueous $N{H}_3$ will precipitate (1) $F{e}^{3+}$ (2) $A{l}^{3+}$ (3) $M{g}^{2+}$ (4) $Z{n}^{2+}$

• A. 1, 2 and 3 are correct.
• B. 1 and 2 are correct.
• C. 2 and 4 are correct.
• D. 1 and 3 are correct.

Answer 1

Answer: (B)

$N{H}_{4}Cl$ and aq $N{H}_3$ are the group reagents for IIIrd group of qualitative inorganic analysis. Hence, they precipitate the radicals belongs to IIIrd group ie,
$F{e}^{3+},A{l}^{3+},C{r}^{3+}$
$F{e}^{3+}+N{H}_{4}OH\to \underset{brownppt.}{Fe{(OH)}_3\downarrow }+N{H}_4^{+}$
$A{l}^{3+}+N{H}_{4}OH\to \underset{whitppt.}{Al{(OH)}_3\downarrow }+N{H}_4^{+}$