Question

A 2.5 mol of hydrazine $N_2H_4$ 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

Answer: (C)

Let the O.N. of N in new compound X be x
$N^{+6}_2H_4----->2N^{+x}+ne^-$
Let the no. of electrons lost per mole = n
$=2(-2)=2x+n(-1)$
$or\,n = 2x + 4 = 2 (x + 2)$
=. No. of electron lost per mole = 2(x + 2)
o. of electrons lost by 2.5 moles $=2.5 \times 2(2+x)$
Now, 2.5 $\times$ 2 (2 + x) = 25
5 ( 2 + x) = 2 5
or 2 + x = 5 or x = + 3