Dental Admissions Test (DAT) Practice Test

What is the oxidation state of carbon in methane (CH4)?

1. 0

2. -1

3. +4

4. -4

The correct answer is: -4

In methane (CH4), the carbon atom is bonded with four hydrogen atoms through single covalent bonds. Carbon typically forms four single bonds in methane, which indicates that it shares four pairs of electrons, giving it a total of eight electrons in its valence shell. Since carbon typically has four valence electrons, in methane carbon has effectively gained four electrons. The oxidation state of an atom in a compound is a measure of the degree of oxidation of that atom, which for carbon in methane is -4.