KMnO4 (acidic/alkaline) is not decolourised by

Question

KMnO4 (acidic/alkaline) is not decolourised by (A) Mohr salt (B) Oxalic acid (C) Benzene (D) Propene

Tardigrade Admin · Accepted Answer

All unsaturated compounds except those which contains delocalisation of

π

-electrons, decolourises alkaline

K M n O_{4}

. While acidic

K M n O_{4}

is decolourised by reducing agents
The acidic/alkaline

K M n O_{4}

is not decolourised by the aromatic compounds due the delocalisation of

π

electrons in the nucleus
Aromatic compounds which have

=

or

\equiv

bond in the side chain decolourise acidic/alkaline

K M n O_{4}

Benzene does not decolourise the acidic/alkaline

K M n O_{4}

due to the delocalisation of

π

electrons
While propene decolourised the alkaline

K M n O_{4}

due to the presence of

=

bond. Ferrous ammonium sulphate and oxalic acid decolourised the

K M n O_{4}

in acidic medium

2 K M n O_{4} + 10 F e S O_{4} + 8 H_{2} S O_{4} \to K_{2} S O_{4} + 2 M n S O_{4} + 5 F e_{2} (S O_{4})_{3} + 8 H_{2} O

2 K M n O_{4} + 5 C_{2} H_{2} O_{4} + 3 H_{2} S O_{4} \to K_{2} S O_{4} + 2 M n S O_{4} + 10 C O_{2} + 8 H_{2} O

Q. KMnO4​ (acidic/alkaline) is not decolourised by