Consider the following reaction

CO2 (g) + H2 (g) - COG) + H2011)

What is being oxidized?

carbon

carbon dioxide

oxygen

hydrogen

Dedio

H2

Explanation:

CO2 + H2 → CO + H2O

↓ (-2). 0. (+2) (-2). (+1) (-2)

↓ ·2 (+2)

+4 (-4)

Write down the oxidation number under each element, each molecule should equal 0 unless there is a charge shown.

Oxygen, always has an oxidation number of - 2 unless in a peroxide.

Hydrogen, is - 1 with metals,+1 with non-metals. Hydrogen loves non-metals!

H2 is zero because any standalone element has an oxidation number of zero

What is being oxidized? Whatever is being oxidized, loses electrons and becomes more positive, it will be a whole molecule, not just an element. In this case, the H in H2 goes from 0 to (+1) so it is the oxidized molecule.