Answer
$C_2H_5OH+3O_2\rightarrow 2CO_2+3H_2O$
Work Step by Step
$C_2H_5OH+O_2\rightarrow CO_2+H_2O$
Add a coefficient of 2 to $CO_2$ to balance $C$.
Add a coefficient of 3 to $H_2O$ to balance $H$.
$C_2H_5OH+O_2\rightarrow 2CO_2+3H_2O$
Add a coefficient of 3 to $O_2$ to balance $O$.
$C_2H_5OH+3O_2\rightarrow 2CO_2+3H_2O$
