Which fo the following can function as a reducing agent ?

Options

A. `(COOH)_2`
B. `H_2SO_4`
C. `KMnO_4`
D. `HNO_3`

Answer

A

Explanation

Reducing agent reduces the other and gets oxidized. This is possible only if one of the atoms (usually central atom ) in the given species is in its lower or lowest oxidation state. In `H_2SO_4, S` has the highest ` O.N. (+6)` , in `KMnO_4, Mn` has the highest ` O.N. (+7)`, and in ` HNO_3, N` has the highest ` O.N. (+5)`. Thus, they cannot further increase their ` O.N.` and hence, cannot act as reducing agents. In oxalic acid, `(COOH)_2`, the oxidation number of `C` is ` +3` which can be increased to ` +4` (highest `O.N.` of C). Thus, oxalic acid can funciton as an oxidizing agent :
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