Question

Two molecules of ethane will need ______ molecules of oxygen for complete combustion.

• A. 2
• B. 9
• C. 7
• D. 5

Answer 1

The correct option is C 7

This is a simple combustion reaction where ethane completely burns to give carbon dioxide and water. The chemical reaction is as follows:

$2{\text{C}}_2{\text{H}}_6+7{\text{O}}_2⟶4{\text{CO}}_2+6{\text{H}}_2\text{O}$

Therefore, the two molecules of ethane will react with seven molecules of oxygen for complete combustion.