second picture is continuation of question

A 0.6447g portion of manganese dioxide was added to an acidic solution in which 1.1402g of a chloride containing sample was dissolved. Evolution of chlorine took place as a consequence of the following reaction: MnO2(s)+2Cl+4H+Mn2++Cl2(g)+2H2O After the reaction was complete, the excess MnO2 was collected by filtration, washed, and weighed, 0.3521g being recovered. Express the result of this analysis in terms of % AlCl3