1 mole of N₂H₄ loses ten moles of electrons to form a new compound Y. Assuming that all the nitrogen appears in the new compound, what is the oxidation state of nitrogen in Y? (There is no change in the oxidation state of hydrogen).

Here, one mole of hydrazine contains two moles of N and loses ten moles of electrons.

If one N atom loses five electrons, then its oxidation number will increase by 5.

Therefore, the oxidation number of N in compound A will be,

 = -2 + 5
 = 3

$\underset{(-2)}{\stackrel{-4}{{\mathrm{N}}_2}}\stackrel{+4}{{\mathrm{H}}_4}\stackrel{-10e^{-}}{\to }\underset{(+3)}{\mathrm{N}}$

Hence, correct option is C.