Question

In presence of $HCl(aq.);H_{2}S$ gas results the precipitation of group-2 cations but not of group-4 cations during qualitative analysis. It is due to:

• A. Lower concentration of $S^{2-}$
• B. Higher concentration of $S^{2-}$
• C. Lower concentration of $H^{+}$
• D. Higher concentration of $H^{+}$

Answer 1

The correct option is B Higher concentration of $S^{2-}$

Due to common ion effect, the ionisation of $H_{2}S$ is suppressed and at low concentration of $S^{2-}$ ions, the second group sulphides are precipitated.