Because there are 2 Cl on the left, we will put a coefficient 2in front of HCl on the right side to balance out the Cl. This would result in an unequal amount of H, with 6 on the right side and 7 in the left, so we have to put a coefficient of 2 in front of C6H5OH and C6H4OH on both sides to balance out the H. By doing this, we would obtain an equal amount of H on both sides. The Carbon is already balanced, and so is the Oxygen.
