Question

As a result of the reaction of 109.5 grams of a solution of hydrochloric acid with an excess of zinc, a gas with a volume of 3.36 litres Was released. Calculate the mass fraction of hydrochloric acid in the original solution

Answer 1

Step-by-step explanation:

Volume of gas produced = 3.36 L

as molar volume of gas at STP is 22.4 L

so

no of moles of H2 = 3.36 ÷ 22.4 = 0.15 mole

from balanced reaction equation

Zn + 2HCl = ZnCl2 + H2

Ratio of no of moles between H2 : HCl is 1:2

as H2 moles = 0.15 mole

so

HCl moles reacted = 0.15 × 2 = 0.3 mole

as HCl molar mass = 1 + 35.5 = 36.5 g/mole

so Mass of 0.3 mole of HCl = 0.3 × 36.5 = 10.85 gram

fraction of HCl in Solution

= 10.85 ÷ 109.5 = 0.1

0.1 ×100 so HCl is 10% of solution mass