A bottle of a commercial reagent-grade hydrochloric acid, HCI, has the following information on its label: Assay 37% HCl by mass; density 1.19 g/mL. Calculate the
volume (ml) of concentrated Hd needed to prepare 250 mL of 0.1M HCI.

The volume of concentrated HCl : 2.073 ml

Given

37% HCl by mass; density 1.19 g/mL

Required

The volume of concentrated HCl

Solution

Conversion to molarity :

37% x 1.19 g/ml =0.4403 g/ml

g/ml to mol/L :

=0.4403 g/ml x 1000 ml/L : 36.5 g/mol

=12.06 mol/L

or we can use formula :

Dilution formula :

M₁V₁=M₂V₂

12.06 M x V₁ = 0.1 M x 0.25 L

V₁ = 0.0021 L = 2.073 ml

dynamic equilibrium is the answer.