$KMnO_4$ decomposes on heating at $513 \ K$ to form $O_2$ along with

$CrO _4^{2-} \underset{ pH = y }{\stackrel{ pH = x }{\longleftrightarrow}} Cr _2 O _7^{2-}$
$pH$ values of $x$ and $y$ are respectively

On heating a mixture of common salt and $K_{2}Cr_{2}O_{7}$ with concentrated $H_{2}SO_{4}$, a gas is evolved. The formula of the gas evolved and the oxidation state of the central metal atom in the gas, respectively, are:

Which of the following are used as catalysts in petroleum cracking?

In the scheme given below,$X$ and $Y$,respectively,are:
$\text{Metal halide} \xrightarrow{\text{aq. NaOH}} \text{White precipitate } (P) + \text{Filtrate } (Q)$
$P \xrightarrow[\text{heat}]{\text{aq. } H_2SO_4, PbO_2 (\text{excess})} X (\text{a coloured species in solution})$
$Q$ $\xrightarrow[\text{warm}]{\text{MnO(OH)}_2, \text{Conc. } H_2SO_4} Y (\text{gives blue-coloration with KI-starch paper})$

When a mixture of manganese dioxide,potassium hydroxide and potassium chlorate is fused,the product obtained is