Question

Which of the following gives the confirmation of thiosulphate ions?

• A. It turns iodine to iodide ions.
• B. It turns orange dichromate solution to green solution.
• C. It gives white precipitate with copper sulphate solution.
• D. It turns pink potassium permanganate to colourless solution.

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A It turns orange dichromate solution to green solution.
B It turns iodine to iodide ions.
C It turns pink potassium permanganate to colourless solution.
D It gives white precipitate with copper sulphate solution.

(i)$2S_2{O}_3^{2-}+I_2\to S_4{O}_6^{2-}+2I^{-}$

(ii)$K_{2}C{r}_2{O}_7+S_2{O}_3^{2-}⟶C{r}_2(S{O}_4{)}_3+K_{2}S{O}_4$(orange dichromate to green)

(iii)$CuS{O}_4+S_2{O}_3^{2-}⟶Cu{S}_2{O}_3\downarrow$

(iv)$KMn{O}_4+S_2{O}_3^{2-}⟶$ colourless.