Transition and InnerTransition Elements - Result Question 131
####31. When $MnO _2$ is fused with $KOH$, a coloured compound is formed, the product and its colour is
(a) $K _2 MnO _4$, purple green
(b) $KMnO _4$, purple
(c) $Mn _2 O _3$, brown
(d) $Mn _3 O _4$, black
(2003, 1M)
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Solution:
- $K _2 MnO _4$ (purple green) is formed which is the first step of preparation of $KMnO _4$.
$2 MnO _2+4 KOH+O _2 \longrightarrow \underset{\text { Purple green }}{K _2 MnO _4}+2 H _2 O$
