When $XO_2$ is fused with an alkali metal hydroxide in the presence of an oxidizing agent such as $KNO_3$,a dark green product is formed which disproportionates in an acidic solution to afford a dark purple solution. $X$ is

$A$ purple colored compound of Manganese $(X)$ decomposes on heating to liberate oxygen and forms compounds of Manganese $(Y)$ and $(Z)$. Compound $(Z)$ reacts with $KOH$ in the presence of potassium nitrate to give compound $(Y)$. Compounds $(X)$,$(Y)$,and $(Z)$ respectively are:

Select the salt whose aqueous solution is not green.

Excess of $KI$ reacts with $CuSO_4$ solution and then $Na_2S_2O_3$ solution is added to it. Which of the statements is incorrect for this reaction?

The starting material for the manufacture of $KMnO_4$ is

Which of the following statement$(s)$ is/are correct?