Answer
1 $C_{2}H_{2}$ + $\frac{5}{2}$ $O_{2}$ --> 2 $C_{}O_{2}$ + 1 $H_{2}O_{}$.
or
2 $C_{2}H_{2}$ + 5 $O_{2}$ --> 4 $C_{}O_{2}$ + 2 $H_{2}O_{}$.
Work Step by Step
1. Write the mentioned reaction:
$C_{2}H_{2}$ + $O_{2}$ --> $C_{}O_{2}$ + $H_{2}O_{}$.
2. Balance the number of Carbon atoms:
1 $C_{2}H_{2}$ + $O_{2}$ --> 2 $C_{}O_{2}$ + $H_{2}O_{}$
3. The number of Hydrogen atoms in each side is equal, so we don't need to change anything.
4. Balance the number of Oxygen atoms:
1 $C_{2}H_{2}$ + $\frac{5}{2}$ $O_{2}$ --> 2 $C_{}O_{2}$ + 1 $H_{2}O_{}$.
5. If you want to get rid of the fraction, just multiply all the equation by 2.
2 $C_{2}H_{2}$ + 5 $O_{2}$ --> 4 $C_{}O_{2}$ + 2 $H_{2}O_{}$.
