Qualitative and Quantitative AnalysishardMCQ SINGLE⭐ Must-Do

In the standard analysis of Group IV cations (), passing through a basic buffer () precipitates all Qualitative and Quantitative Analysis Chemistry Question

Question

In the standard analysis of Group IV cations ($Zn^{2+}, Mn^{2+}, Co^{2+}, Ni^{2+}$), passing $H_2S$ through a basic buffer ($NH_4OH/NH_4Cl$) precipitates all four sulphides. If, instead, $H_2S$ is passed through a strongly acidic solution ($>0.5\text{ M HCl}$) containing these same four ions, what will precipitate?

Answer: D

💡 Solution & Explanation

Group IV sulphides have relatively high $K_{sp}$ values. The high concentration of $H^+$ in a $>0.5\text{ M HCl}$ solution strongly suppresses the ionization of $H_2S$ (common ion effect). The resulting $S^{2-}$ concentration is so incredibly low that it cannot exceed the $K_{sp}$ for any Group IV sulphide, resulting in zero precipitation.

💬
Still have doubts about this question?
Send it to our AI chemistry tutor on WhatsApp — gets answered in minutes
Ask on WhatsApp →

Practice 22,000+ questions like this

AI-adaptive practice, video lectures, and full IChO (Chemistry Olympiad) content — all in one place.

JEE Advanced · JEE Mains · NEET · IChO · AP Chemistry