Question

A mole of $N_2{H}_4$ 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 number of hydrogen)

• A. -1
• B. -3
• C. +3
• D. +5

Answer 1

Answer: (C)

$N_2{H}_4-10e^{-}\to Y$ (with two N atoms)
Total O.N. of two $N$ atoms in $N_2{H}_4$ is
$2x+4=0$ or $2x=-4$
Since it loses $10$ moles of electrons, therefore, total O.N. of two N atoms increases by $10$, i.e., the total O.N. of two N-atoms is
$Y=-4+10=+6$
$\therefore$ O.N. of each N atom in $Y=+3$.