Question

What is the oxidation state of each element in $CO{H_2}$ ?

Answer 1

To know the oxidation state of each element of the given compound $CO{H_2}$ , we should go through one by one each and every element of this compound. We will check the electronegativity properties and the charge on every element separately, and then decide the oxidation state.

Complete step by step solution:
Start by assigning formal oxidation states to the most electronegative elements, then discover the positive limits of the least electronegative elements. Elements in the middle are determined by conservation of charge.
Start with oxygen, which is more electronegative than any element except fluorine. The preferred oxidation state of $O$ is -2.
Next is hydrogen $(H)$ , which has a preferred oxidation state of +1.
The sum of all oxidation states must equal the overall charge on the molecule (in this case, zero). If we let $x$ represent the oxidation state of carbon , then:
$- 2 + 2 \cdot ( + 1) + x = 0$
Solving for $x$ gives $x = 0$
Therefore, the formal oxidation state of carbon in this molecule is zero. Note that carbon can adopt formal oxidation states from +4 (as in $C{O_2}$ ) to -4 (as in $C{H_4}$ ).

Note:
The oxidation state, sometimes referred to as oxidation number, describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component.