On heating $KMnO_4$,which one of the following is not formed?

$A$ first row transition metal with the highest enthalpy of atomization,upon reaction with oxygen at high temperature,forms oxides of the formula $M_2O_n$ (where $n=3, 4, 5$). The 'spin-only' magnetic moment value of the amphoteric oxide from the above oxides is $......$ $BM$ (nearest integer). (Given atomic number: $Sc: 21, Ti: 22, V: 23, Cr: 24, Mn: 25, Fe: 26, Co: 27, Ni: 28, Cu: 29, Zn: 30$)

Which of the following statements is incorrect?

Identify the correct $(T)$ and incorrect $(F)$ statements from the following:
$(a)$ $MnO_4^{2-}$ is diamagnetic.
$(b)$ $MnO_4^-$ is green and $MnO_4^{2-}$ is purple.
$(c)$ $K_2Cr_2O_7$ is yellow.
$(d)$ $K_2Cr_2O_7$ is orange.

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 $H_2SO_4$ to give a pungent gas $Z$. Identify $X, Y$ and $Z$.

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