Compare the products of complete and incomplete combustion of methane:

The correct option is: Complete → CO₂ + H₂O; Incomplete → CO + H₂O.

Step-by-Step Explanation:

1. Understanding Combustion of Hydrocarbons:
Combustion is a chemical reaction where a fuel (in this case, methane, CH₄) reacts with oxygen (O₂) to release energy in the form of heat and light. The products of this reaction depend heavily on the availability of oxygen.

2. Complete Combustion:
Complete combustion occurs when there is a plentiful supply of oxygen. Under these conditions, the hydrocarbon is fully oxidized. The carbon atoms in methane (CH₄) combine with oxygen to form carbon dioxide (CO₂), and the hydrogen atoms combine with oxygen to form water (H₂O).
The balanced chemical equation for the complete combustion of methane is:
$${\mathrm{CH}}_4+2O_2\to {\mathrm{CO}}_2+2H_{2}O$$ Thus, the products of complete combustion are carbon dioxide (CO₂) and water (H₂O).

3. Incomplete Combustion:
Incomplete combustion occurs when the oxygen supply is limited or restricted. Because there is not enough oxygen to fully oxidize all the carbon to carbon dioxide, toxic carbon monoxide (CO) gas is produced instead of (or alongside) carbon dioxide. Water (H₂O) continues to be a product of the hydrogen oxidation.
One of the primary chemical equations representing the incomplete combustion of methane is:
$$2{\mathrm{CH}}_4+3O_2\to 2\mathrm{CO}+4H_{2}O$$ Thus, the products of incomplete combustion are carbon monoxide (CO) and water (H₂O).

4. Conclusion:
Comparing the two processes, complete combustion yields carbon dioxide and water, while incomplete combustion yields carbon monoxide and water. This matches the correct option perfectly.