Answer:
H3PO4 + 5HCl → PCl5 + 4H2O
Explanation:
In a chemical reaction, the number of atoms of each element must be the same on both sides of the equation. Notice that, originally, there's only one atom of chlorine on the left side and five atoms of chlorine on the right. The coefficient of 5 is added to the HCl compound to correct this. However, now there are eight atoms of hydrogen on the left and only two on the right. Adding the coefficient of 4 to the H2O compound balances the hydrogen and also balances oxygen on both sides at the same time.
