Transition and InnerTransition Elements - Result Question 103
####1. Thermal decomposition of a Mn compound $(X)$ at $513 K$ results in compound $(Y), MnO _2$ and a gaseous product. $MnO _2$ reacts with $NaCl$ and concentrated $H _2 SO _4$ to give a pungent gas $Z$. $X, Y$ and $Z$, respectively, are (2019 Main, 12 April II)
(a) $K _3 MnO _4, K _2 MnO _4$ and $Cl _2$
(b) $K _2 MnO _4, KMnO _4$ and $SO _2$
(c) $KMnO _4, K _2 MnO _4$ and $Cl _2$
(d) $K _2 MnO _4, KMnO _4$ and $Cl _2$
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Solution:
- Thermal decomposition of $Mn$ compound $(X)$, i.e. $KMnO _4$ at $513 K$ results in compound $Y$ (i.e. $\left.K _2 MnO _4\right), MnO _2$ and a gaseous product. $MnO _2$ reacts with $NaCl$ and concentrated $H _2 SO _4$ to give a pungent gas $Z$ (i.e. $Cl _2$ ). The reactions involved are as follows :
$$ \begin{aligned} & \underset{(X)}{2 KMnO _4} \underset{\Delta}{513 K} \underset{(Y)}{K _2 MnO _4}+MnO _2+O _2(g) \ & MnO _2+4 NaCl+4 H _2 SO _4 \longrightarrow \ & MnCl _2+4 NaHSO _4+2 H _2 O+Cl _2(g) \ & (Z) \ & \text { Pungent gas. } \end{aligned} $$
