The oxidation number of iodine varies from:

$A$ compound contains $x$,$y$,and $z$ atoms. The oxidation number of $x$ is $+3$,$y$ is $-5$,and $z$ is $+1$. The possible formula of the compound is:

$2$ mole of $N_2H_4$ loses $16$ mole of electrons and is converted to a new compound $X$. Assuming that all of the $N$ atoms appear in the new compound,what is the oxidation state of $N$ in $X$?

The oxidation number of carbon in $H_2C_2O_4$ is:

The oxidation state of nitrogen is incorrectly given for:
Compound $\to$ Oxidation state

What is the oxidation number of underlined species in $\underline{P}F_6^{-}$ and $\underline{V}_2 O_7^{4-}$ ions respectively?