# Question #ffcd9

This is the value of a balance chemical reaction equation! You can see directly that the ratio of HCl to $F {e}_{2} {O}_{3}$ is 6:1, and with 2 Fe in the oxide the molar ratio of HCl to Fe(III) is 3:1. Therefore, if 3 moles of Fe(III) are used, the amount of HCl required is 3*3 = 9 moles.