What is the standard half-cell potential for the oxidation of methane under acidic conditions? The reaction for methane is as follows:

CH4 (g) + 2H20 (l) → CO2 + 8H⁺ + 8e⁻

What element is oxidized and how does its oxidation state change?

The element that is oxidized is carbon.

Its oxidation state increased. It increased from - 4 to + 4

Explanation:

Oxidation is a process that involves increase in oxidation number.

The oxidation number of carbon in CH4 is - 4

C + (1*4) = 0

C + 4 = 0

C = 0 - 4 = - 4

The oxidation number of carbon in CO2 is + 4

C + (2*-2) = 0

C - 4 = 0

C = 0+4 = 4

Increase in the oxidation number of carbon from - 4 to + 4 means carbon is oxidized