Question

What is the change in oxidation number of carbon in the following reaction ?
$C{H}_4(g)+4C{l}_2(g)\to CC{l}_4(l)+4HCl(g)$

• A. +4 to +4
• B. 0 to +4
• C. -4 to +4
• D. 0 to -4

Answer 1

Answer: (C)

Oxidation number of $C$ in $C{H}_4$ is $-4$
as $x+4=0$$x=-4(x$ is oxidation state of carbon)
oxidation of $C$ in $CC{l}_4$ is $+4$
as $x-4=0x=+4$
$\therefore$ Change in oxidation state of carbon is from $-4$ to $+4$