Question

To an aqueous solution containing ions such as$A{l}^{3+},Z{n}^{2+},C{a}^{2+},F{e}^{3+},N{i}^{2+},B{a}^{2+}\text{and}C{u}^{2+}$ was added conc. $HCl$, followed by $H_{2}S$.

The total number of cation precipitated during this reactions is/are :

• A. 2
• B. 4
• C. 3
• D. 1

Answer 1

The correct option is D 1

Only group I and II cations will get precipitated.

$\therefore$ Only $C{u}^{2+}$ gets precipitated here.

$A{l}^{3+}$ and $F{e}^{3+}$ sulphides hydrolyse in water. $N{i}^{2+}$ and $Z{n}^{2+}$ require basic medium with $H_{2}S$ to form ppt $C{a}^{2+}$ and $B{a}^{2+}$ sulphides are soluble hence we will receive only $CuS$ ppt.