In given reaction \(3MnO_4^{2-} + 4H^+ \longrightarrow 2MnO_4^- + MnO_2 + 2H_2O\) oxidation state shown by \(Mn\) are

(A) VI

(B) II

(C) VII

(D) IV

(E) V

Choose the correct answers from the options given below:

A, C and D only

The correct answer is option 2. A, C, and D only.

Let us review the oxidation states of each of the compounds containing \(Mn\):

The given reaction is:

\[3MnO_{4}^{2-} + 4H^{+} \longrightarrow 2MnO_{4}^{-} + MnO_{2} + 2H_{2}O\]

On the reactant side (\(3MnO_{4}^{2-} + 4H^{+}\)), the permanganate ion (\(MnO_{4}^{2-}\)) has a known oxidation state of \(+6\) for manganese.

On the product side (\(2MnO_{4}^{-} + MnO_{2} + 2H_{2}O\)), the oxidation states are:

1. In \(MnO_{4}^{-}\): \(+7\)
2. In \(MnO_{2}\): \(+4\)

Based on the analysis, the oxidation states of manganese in the reaction are \(+6\), \(+7\) and \(+4\), which matches with options A, C, and D.

So, the correct matching is 2. A, C, and D only