The product and its colour when $\mathrm{MnO}_2$ is fused with KOH in presence of $\mathrm{O}_2$ :
$\mathrm{Mn}_2 \mathrm{O}_3$, Brown
$\mathrm{MnO}_2$, Black
$\mathrm{KMnO}_4$, Purple
$\mathrm{K}_2 \mathrm{MnO}_4$, Dark green
$$ \text { Identify the aromatic compounds among the given set based on Huckel's rule: } $$

I, II, III
II, III, IV
I, II, IV
I, III, IV
In the redox reaction, taking place in acidic medium: $\mathrm{X} \mathrm{MnO}_4^{-}(\mathrm{aq})+\mathrm{YSO}_2(\mathrm{~g}) \rightarrow \mathrm{Mn}^{+2}(\mathrm{aq})+\mathrm{HSO}_4^{-}(\mathrm{aq})$, the ratio of $X: Y$ in a stoichiometrically balanced equation will be
$5:2$
$1:2$
$2:5$
$2: 3$
At $30^{\circ} \mathrm{C}$ the solubility of $\mathrm{PbI}_2$ salt in 0.2 M KI solution will be $X$, if the solubility product of $\mathrm{PbI}_2$ at $30^{\circ} \mathrm{C}$ is $2.4 \times 10^{-8}$. Identify the value of $X$.
$4.8 \times 10^{-7} \mathrm{M}$
$6.0 \times 10^{-7} \mathrm{M}$
$2.4 \times 10^{-8} \mathrm{M}$
$3.0 \times 10^{-8} \mathrm{M}$
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