Question

Question 1.36 Chlorine is prepared in the laboratory by treating manganese dioxide (MnO2) with aqueous hydrochloric acid according to the reaction

4HCl(aq) + MnO2(s)→2H2O(l) + MnCl2(aq) + Cl2(g)

How many grams of HCl react with 5.0 g of manganese dioxide?

Class XI Some Basic Concepts of Chemistry Page 25

Answer 1

4HCl (aq) + MnO₂ (s) -------> 2H₂O (l) + MnCl₂(aq) + Cl₂ (g).

here we see that ,
1 mole of MnO₂ react with 4 mole of HCl .

mass of 1 mole of MnO₂ = 55 + 2 × 16 = 87 g
mass of 4 mole of HCl = 4 × (1 + 35.5) = 4 × 36.5 g

e.g ,

87g of MnO₂ react with 4 × 36.5 g of HCl
so, 1 g of MnO₂ react with 4 × 36.5/87 g of HCl
so, 5g of MnO₂ react with 4 × 36.5 × 5/87 g of HCl
= 4 × 36.5 × 5/87 g of HCl
= 8.39 g of HCl

hence, 8.39 g of HCl reacts with 5g of MnO₂.