If $HNO_3$ changes into $N_2O$,the oxidation number of nitrogen is changed by

Oxidation state of oxygen in $F_2O$ is

The oxidation number of $H$ in $KH$,$MgH_2$,and $NaOH$ are respectively

Calculate the oxidation number of oxygen in potassium ozonide $(KO_3)$.

In how many of the following compounds of sulphur,the oxidation state of sulphur atom is $+6$?
$H_2S_2O_8, H_2SO_5, H_2SO_3, H_2SO_4, H_2S_2O_7, SO_2Cl_2, SOCl_2$

Oxidation number of $N$ in $HNO_3$ is