In Chromyl chloride,the oxidation state of chromium is $+6$.

Assign the oxidation number to the underlined element in each of the following species:
$1$. $K_2\underline{Mn}O_4$
$2$. $Ca\underline{O}_2$
$3$. $Na\underline{B}H_4$
$4$. $KAl(\underline{S}O_4)_2 \cdot 12H_2O$

In ferrous ammonium sulphate,the oxidation number of $Fe$ is:

The oxidation state of $Mn$ in $K_2MnO_4$ is:

Match the following compounds with their respective oxidation numbers of the central atom or specific element:

Compound	Oxidation number
$1$. $C_2H_6$	$a$. $+3$
$2$. $H_2O_2$	$b$. $+6$
$3$. $LiAlH_4$	$c$. $-3$
$4$. $HO_2^-$	$d$. $-1$
$5$. $PbSO_4$	$e$. $+1$

The oxidation states of $S$ atoms in Caro's acid and Marshall's acid are