Chemistry - Salt Analysis Question with Solution | TestHub

Question Explanation: Sequence of reactance of ${\mathrm{S}}_2{\mathrm{O}}_3^{2-}$

Concept: Qualitative analysis of thiosulfate ion

Solution:

Two thiosulfate ions react with ${\mathrm{HgCl}}_2$ to produce a white precipitate of ${\mathrm{HgS}}_2{\mathrm{O}}_3$, which on heating converts into a black precipitate of $\mathrm{HgS}$.↓

$N{a}_2{\mathrm{S}}_2{\mathrm{O}}_3+HgC{l}_2\to Hg{S}_2{O}_3\stackrel{\Delta }{\downarrow \to }HgS\downarrow$

White ppt(N) Black ppt (O)