The oxidation state of $N$ in $HNO_4$ is

In which of the following does phosphorus have an oxidation state of $+3$?

An acidified solution of sodium thiosulfate is unstable because in thiosulfate,the two sulfur atoms are in:

What is the oxidation number of nitrogen in $N_3H$?

One mole of $N_2H_4$ loses $10 \ mol$ of electrons to form a new compound $Y$. Assuming that all nitrogen atoms appear in the new compound,what is the oxidation state of $N$ in $Y$? (There is no change in the oxidation state of hydrogen)

In which of the following substances is the oxidation state of sulfur $-1$?