One mole of $N_2{H}_4$ loses 10 moles electron to form new compound X, assuming that all nitrogen appears in new compound. There is no change in oxidation state of H. What is the oxidation state on N in X.

Oxidation state of N is hydrazine is – 2
1 mole of hydrazine contains 2 moles of N and loses
10 moles of electrons. Hence 1 N atom will lose
5 electrons, Hence, its oxidation number will increase by 5.
Hence, the oxidation number of N in compound will be – 2 + 5 = + 3