Answer:
Option C . CO2(g) + H2O(g)
Step-by-step explanation:
When hydrocarbon undergoes combustion, carbon dioxide (CO2) and water (H2O) are produced.
C2H4(g) + O2(g) —› CO2(g) + H2O(g)
Thus, the product of the unbalanced combustion reaction is:
CO2(g) + H2O(g)
Thus, we can balance the equation as follow:
C2H4(g) + O2(g) —› CO2(g) + H2O(g)
There are 2 atoms of C on the left side and 1 atom on the right side. It can be balanced by putting 2 in front of CO2 as shown below:
C2H4(g) + O2(g) —› 2CO2(g) + H2O(g)
There are 4 atoms of H on the left side and 2 atoms on the right side. It can be balanced by putting 2 in front of H2O as shown below:
C2H4(g) + O2(g) —› 2CO2(g) + 2H2O(g)
There are a total of 6 atoms of O on the right side and 2 atom on the left side. It can be balanced by putting 3 in front of O2 as shown below:
C2H4(g) + 3O2(g) —› 2CO2(g) + 2H2O(g)
Thus, the equation is balanced.