Chemistry - Salt Analysis Question with Solution | TestHub

Na₂S₂O₃ + S $\stackrel{boiling}{\to }$ X Sulfur reacts with sodium thiosulfate to form sodium tetrathionate, Na₂S₄O₆. On crystallization, X forms the hydrated salt Na₂S₂O₃·5H₂O (hypo).

X gives a violet color with FeCl₃ due to the formation of the ferric thiosulfate complex $[Fe(S_2{O}_3{)}_2{]}^{-}$.

Therefore, X = Na₂S₂O₃ and B = $[Fe(S_2{O}_3{)}_2{]}^{-}$. Answer: (B)