Question

A 2.5 mol of hydrazine `N_(2)H_(4)` loses 25 mole of electrons is being converted to a new compound X. Assuming that all of the nitrogen appears in the new compound, what is the oxidation state of nitrogen in compound X ?
A. `-1`
B. `-2`
C. `+3`
D. `+4`

Answer 1

Correct Answer - C
Let the O.N of N in new compound X be be x
`overset(+6)(N_(2))H_(4)rarr overset(+x)(2N)+n e^(-)`
Let the no. of electron lost per mole of = n
`:. 2(-2) = 2x + n (-1)`
or `n = 2x + 4 = 2 (x+2)`
`:.` No. of electron lost per mole `= 2(x+2)`
no. of electrons lost by 2.5 mols `= 2.5 xx 2(2+x)`
Now, `2.5 xx 2(2+x) = 25`
`5(2+x) = 25`
or `2 + x = 5 or x = +3`