The coefficient for Oxygen in the balanced reaction : 3
Further explanation
Given
Reaction
C₂H₄ + _ _ O₂ ⇒ _ _ CO₂ + _ _ H₂O
Required
Oxygen coefficient
Solution
C₂H₄ + aO₂ ⇒ bCO₂ + cH₂O
C, left=2, right=b⇒b=2
H, left=4, right=2c⇒2c=4⇒c=2
O, left=2a, right=2b+c⇒2a=2b+c⇒2a=2.2+2⇒2a=6⇒a=3
The equation becomes :
C₂H₄ + 3O₂ ⇒ 2CO₂ + 2H₂O