Question

help with balancing . ? H3PO4+ HCl ->PCl5 +H2O

Answer 1

the first thing to balance is the chlorine
\[H_3PO_4+ 5HCl \rightarrow PCl_5 +4H_2O\]

Answer 2

thanks! how do you kno what to balance first?

Answer 3

well it depends , but in this case Cl appeared in one term only one each side of the equation and had a big number (5). I would generally do the oxygen and hydrogen last because they usually occur in many terms