Question

In the following reaction sequence in aqueous solution, the species X, Y and Z, respectively, are

$S_2{O}_3^{2-}\stackrel{A{g}^{+}}{\to }\underset{\text{solution}}{\underset{\text{clear}}{X}}\stackrel{A{g}^{+}}{\to }\underset{\text{precipitate}}{\underset{\text{white}}{Y}}\stackrel{\text{with time}}{\to }\underset{\text{precipitate}}{\underset{\text{black}}{Z}}$

• A. $\left[Ag\right(S_2{O}_3{)}_2{]}^{3-},A{g}_2{S}_2{O}_3,A{g}_{2}S$
• B. $\left[Ag\right(S_2{O}_3{)}_3{]}^{5-},A{g}_{2}S{O}_3,A{g}_{2}S$
• C. $\left[Ag\right(S{O}_3{)}_2{]}^{3-},A{g}_2{S}_2{O}_3,Ag$
• D. $\left[Ag\right(S{O}_3{)}_3{]}^{3-},A{g}_{2}S{O}_4,Ag$

Answer 1

The correct option is A $\left[Ag\right(S_2{O}_3{)}_2{]}^{3-},A{g}_2{S}_2{O}_3,A{g}_{2}S$

$A{g}^{+}+2S_2{O}_3^{2-}⟶\underset{\text{clear solution}}{{\underset{X}{\left[Ag\right(S_2{O}_3{)}_2]}}^{3-}}\stackrel{A{g}^{+}}{\to }\underset{\text{(white)}}{\underset{Y}{A{g}_2{S}_2{O}_3}}\stackrel{\text{with time}}{\to }\underset{\text{(black)}}{\underset{Z}{A{g}_{2}S}}$

$A{g}_2{S}_2{O}_3+H_{2}O⟶A{g}_{2}S+H_{2}S{O}_4$