Q3 / 75 · JEE Main 2025 (28 Jan Shift 1) · Chemistry

Which of the following oxidation reactions are carried out by both $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ and $\mathrm{KMnO}_4$ in acidic medium? A. $\Gamma^{-} \rightarrow \mathrm{I}_2$ B. $S^{2-} \rightarrow S$ C. $\mathrm{Fe}^{2+} \rightarrow \mathrm{Fe}^{3+}$ D. $\Gamma^{-} \rightarrow \mathrm{IO}_3{ }^{-}$ E. $\mathrm{S}_2 \mathrm{O}_3{ }^{2-} \rightarrow \mathrm{SO}_4{ }^{2-}$ Choose the correct answer from the options given below:

  • A
    C, D and E Only
  • B
    B, C and D Only
  • C
    A, D and E Only
  • Correct answer
    D
    A, B and C Only

Solution

$\mathrm{I}^{-} \xrightarrow{\mathrm{OH}} \mathrm{IO}_3^{-}$ $\mathrm{S}^{-2} \xrightarrow{\mathrm{H}^{+}} \mathrm{S}$ $\mathrm{S}_2 \mathrm{O}_3^{2-} \xrightarrow{\mathrm{OH}} \mathrm{SO}_4^{2-}$ $\begin{aligned} & \mathrm{Fe}^{+2} \longrightarrow \mathrm{Fe}^{+3} \\ & \mathrm{~S}_2 \mathrm{O}_3^{2-} \xrightarrow{\mathrm{H}^{+}} \mathrm{S} \downarrow+\mathrm{SO}_4^{2-} \end{aligned}$

Hence, the correct answer is option: 'D'.

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