Question

The oxidation number of C in HNC is:
(A) +2
(B) -3
(C) +3
(D) 0

Answer 1

We must keep in mind the basics of oxidation and reduction. Oxidation means a loss of hydrogen atom while reduction means a gain of hydrogen atom. Also, we can formulate oxidation as the gain of an electron and reduction as the loss of an electron. Accordingly, we can easily solve the given question.

Complete step-by step answer:
We know that the oxidation number of Hydrogen atom (H) is $+1 .$ As Nitrogen is more electronegative than Carbon, the oxidation number of Nitrogen is - 3. The Net charge on the compound is zero.
Now, we can find oxidation number of Carbon atom from the given equation:
Let the oxidation number of Carbon atom in the given compound be $\mathrm{x}$, $1+(-3)+x=0$
$\mathrm{x}=+2$

Hence, the correct option is $\mathrm{A}$

Note: We might get confused by the term reduction meaning a gain in hydrogen atom. But the correct way to remember this is that hydrogen atom has a positive charge and as reduction also means a loss of electron or a loss in negative charge, we can determine that a gain in hydrogen atom is equivalent to a loss in electron. Hence, we can easily remember the concept of reduction this way.