Paris green is

Chromite ore $\xrightarrow{Na_2CO_3 + O_2} A$ $\xrightarrow[NaOH]{H_2SO_4} B$. Which of the following is correct?

Fusion of $MnO_2$ with $KOH$ in presence of $O_2$ produces a salt $W$. Alkaline solution of $W$ upon electrolytic oxidation yields another salt $X$. The manganese containing ions present in $W$ and $X$,respectively,are $Y$ and $Z$. Correct statement$(s)$ is (are)
$(1)$ $Y$ is diamagnetic in nature while $Z$ is paramagnetic
$(2)$ Both $Y$ and $Z$ are coloured and have tetrahedral shape
$(3)$ In both $Y$ and $Z$,$\pi$-bonding occurs between $p$-orbitals of oxygen and $d$-orbitals of manganese.
$(4)$ In aqueous acidic solution,$Y$ undergoes disproportionation reaction to give $Z$ and $MnO_2$.

Presence of $Cr$ in steel makes it

Which of the following statements are $INCORRECT$?
$A$. All the transition metals except scandium form $MO$ oxides which are ionic.
$B$. The highest oxidation number corresponding to the group number in transition metal oxides is attained in $Sc_2O_3$ to $Mn_2O_7$.
$C$. Basic character increases from $V_2O_3$ to $V_2O_4$ to $V_2O_5$.
$D$. $V_2O_4$ dissolves in acids to give $VO_4^{3-}$ salts.
$E$. $CrO$ is basic but $Cr_2O_3$ is amphoteric.
Choose the correct answer from the options given below:

Potassium permanganate on heating at $513 \ K$ gives a product which is :