When $M n O_{2}$ is fused with $K O H$ in the presence of $K N O_{3}$ as an oxidizing agent, it gives a dark green compound (A).
Compound (A) disproportionates in acidic solution to give purple compound (B).
An alkaline solution of compound (B) oxidises $K I$ to compound (C) whereas an acidified solution of compound (B) oxidises $K I$ to (D). Identify (A), (B), (C), and (D).

Open in App

Solution

$2 M n O_{2} + 4 K O H \to 2 K_{2} M n O_{4} (A) D a r k G r e e n + 2 H_{2} O$
$3 M n O_{4}^{2 -} + 4 H^{+} \to 2 M n O_{4}^{-} (B) P u r p l e + M n O_{2} + 2 H_{2} O$
In alkaline solution
In this reaction iodine is oxidised to iodate:
$2 M (B) n O_{4}^{-} + H_{2} O + I^{-} \to 2 M n O_{2} + 2 O H^{-} + I (C) O_{3}^{-}$
In acidified solutions:
Iodine is liberated from potassium iodide:
$10 I^{-} + 2 M (B) n O_{4}^{-} + 16 H^{+} \to 2 M n^{2 +} + 8 H_{2} O + 5 (D) I_{2}$

Suggest Corrections

Similar questions

Q. Choose the correct answer from the alternative given.
When an oxide of manganese (P) is fused with KOH in the presence of an oxidizing agent and dissolved in water, it gives a dark green solution of compound (Q). Compound (Q) disproportionates in neutral or acidic solution to give purple compound (R). An alkaline solution of compound (R) oxidizes potassium iodide solution to a compound (S) and compound (P) is also formed. Compounds P to S are:

M n O_{2}

when fused with KOH and oxidized in air gives a dark green compound X. In acidic X. In acidic solution, X undergoes disproportion to give an intense purple compound Y and

M n O_{2}

. The compounds X and Y. respectively, are

$M n O_{2}$ when fused with KOH and oxidized in air gives a dark green compound X. In acidic X. In acidic solution, X undergoes disproportion to give an intense purple compound Y and $M n O_{2}$ . The compounds X and Y respectively, are

Q. (a) An organic compound (A) of molecular formula

C_{6} H_{6} O

gives violet colour with neutral ferric chloride. Compound (A) when refluxed with

C H {C l}_{3}

and

N a O H

gives two isomers (B) and (C). Compound (A) when added ot diazomethane in alkaline medium gives an ether (D). Identify (A), (B), (C) and (D). Explain the reactions.

(b) Compound (A) is an orange red crystal and also a powerful oxidising agent. Compound (A) when treated with potassium chloride and concentrated sulphuric acid evolves coloured gas (B). When

K O H

reacts with (A) an yellow solution of (C) is obtained. Identify (A), (B) and (C). Explain the reactions.

Q. Pyrolusite on heating with

K O H

in presence of air gives a dark green compound (A). The solution of (A) on treatment with sulphuric acid gives a purple colour compound (B). Compound (B) with concentrated

H_{2} S O_{4}

gives (C) which can decompose to (D) and

O_{2}

. What is the number of unpaired electrons in the cation of (D)?

Join BYJU'S Learning Program