Chlorine is prepared in the laboratory by treating manganese dioxide (MnO2) with aqueous hydrochloric acid according to the reaction
4HCl (aq) + MnO2(*) → 2H2O(l) + MnCl2(aq) + Cl2(g)
How many grams of HCl react with 5.0 g of manganese dioxide?
1 mol of MnO2 = 55+32 g = 87 g
87 g of MnO2 react with 4 ***** of HCl i.e. 4×36.5 g = 146 g of HCl.
∴ 5.0 g of MnO2 will react with HCl = 146/87×5.0 g = 8.40 g.
