When H_2S is passed through a solution contai | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) In qualitative analysis,$H_2S$ is a weak acid that dissociates as: $H_2S \rightleftharpoons 2H^+ + S^{2-}$.When $HCl$ is added,the concentration o

Vedclass · Accepted Answer

The presence of $HCl$ decreases the concentration of sulfide ions.

Vedclass · Answer

(A) In qualitative analysis,$H_2S$ is a weak acid that dissociates as: $H_2S \rightleftharpoons 2H^+ + S^{2-}$.When $HCl$ is added,the concentration of $H^+$ ions increases significantly due to the common ion effect.According to Le Chatelier's principle,this suppresses the dissociation of $H_2S$,thereby drastically reducing the concentration of $S^{2-}$ ions.Group $II$ cations precipitate at very low $S^{2-}$ concentrations,whereas group $IV$ cations require a higher concentration of $S^{2-}$ to exceed their solubility product $(K_{sp})$,which is not achieved in the presence of $HCl$.

When $H_2S$ is passed through a solution containing $HCl$ for qualitative analysis,it does not precipitate group $IV$ cations. Why is this?

Similar Questions

Calculate $[S^{2-}]$ and $[HS^{-}]$ of the solution which contains $0.1 \ M \ H_2S$ and $0.3 \ M \ HCl$.
[$K_{a1} = 1.0 \times 10^{-7}$ and $K_{a2} = 1.3 \times 10^{-13}$ for $H_2S$]

Solubility of $AgCl$ in conc. $HCl$ is ...... than in water.

Which is not an example of common ion effect?

If the maximum concentration of $PbCl_2$ in water at $298 \, K$ is $0.01 \, M$,what is its maximum concentration in $0.1 \, M \, NaCl$ solution?

Vedclass Test Series

Exam Paper Generator

Online Exam Module