Chemistry - Ionic Equilibrium Question with Solution | TestHub

Question Explanation: Identifying a reaction where at least one product is insoluble.

Concept: Solubility Rules and Precipitation Reactions.

(A) $2{\mathrm{Cr}}^{3+}+3{\mathrm{S}}_2{\mathrm{O}}_8^{2-}+7{\mathrm{H}}_2\mathrm{O}\to {\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}+6{\mathrm{SO}}_4^{2-}+14{\mathrm{H}}^{+}{\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}$ and ${\mathrm{SO}}_4^{2-}$ are generally soluble.

(B) ${\mathrm{Mn}}^{2+}+{\mathrm{S}}_2{\mathrm{O}}_8^{2-}+2{\mathrm{H}}_2\mathrm{O}\to {\mathrm{MnO}}_2(\mathrm{s})+2{\mathrm{SO}}_4^{2-}+\underset{\text{ (so lub }}{4{\mathrm{H}}^{+}}$

(Insoluble)

(C) $2{\mathrm{I}}^{\ominus }+{\mathrm{S}}_2{\mathrm{O}}_8^{2-}+2{\mathrm{Fe}}^{3+}\to {\mathrm{I}}_2^{(\mathrm{s})}+2{\mathrm{SO}}_4^{2-}+\underset{\text{ (Insolub le) }}{2{\mathrm{Fe}}^{2+}}$

(D) $3{\mathrm{MnO}}_4^{2-}+4{\mathrm{H}}^{+}\to 2{\mathrm{MnO}}_4^{-}+{\mathrm{MnO}}_2+2{\mathrm{H}}_2\mathrm{O}$

(soluble) (Insoluble)

Final Answer: A.