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

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

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.