In the molecule formaldehyde CH2O , the oxidation state of carbon can be determined by assigning oxidation numbers to each atom in the molecule. Hydrogen has an oxidation number of +1, and oxygen has an oxidation number of -2. The molecule can be represented as:C + 2 H + O = 0Let the oxidation state of carbon be x. Then, the equation becomes:x + 2 +1 + -2 = 0x + 2 - 2 = 0x = 0So, the oxidation state of carbon in formaldehyde is 0.Now, let's identify the elements being reduced and oxidized in the following reaction:2CH3OH + 3O2 2CO2 + 4H2OFirst, assign oxidation numbers to each element in the reactants and products:CH3OH: C -2 , H +1 , O -2 O2: O 0 CO2: C +4 , O -2 H2O: H +1 , O -2 Comparing the oxidation numbers of the elements in the reactants and products:1. Carbon in CH3OH goes from -2 to +4, which means it loses electrons. This is an oxidation process. So, carbon is being oxidized.2. Oxygen in O2 goes from 0 to -2, which means it gains electrons. This is a reduction process. So, oxygen is being reduced.