Chemistry - Redox Reactions Question with Solution | TestHub

The chemical formula of methanal (formaldehyde) is $HCHO$.

Let the oxidation number of carbon be $x$.

The oxidation number of hydrogen is $+1$ and that of oxygen is $-2$.

The sum of oxidation numbers of all atoms in a neutral molecule is zero.

$x+2(+1)+1(-2)=0$

$x+2-2=0$

$x=0$

The oxidation number of carbon in methanal is zero.

Answer: zero