Question

A certain supply of hydrochloric acid has a concentration of 36.0% by mass HCl. The density of the solution is 1.19g/mol .calculate the molar concentration and molality of HCl .[ Mr ( HCl)=36.5g/mol]

Answer 1

To calculate the molar concentration of HCl, we need to first determine the molarity of the solution:

Molarity (M) = (mass percent HCl / Mr HCl) / (density of solution)
Molarity (M) = (36.0 / 36.5) / 1.19
Molarity (M) = 0.9864 / 1.19
Molarity (M) = 0.8275 M

To calculate the molality of HCl, we need to use the formula:

Molality (m) = (mass percent HCl / Mr HCl) / (100 - mass percent HCl)
Molality (m) = (36.0 / 36.5) / (100 - 36.0)
Molality (m) = 0.9864 / 64
Molality (m) = 0.0154 m

Therefore, the molar concentration of HCl in the solution is 0.8275 M and the molality of HCl is 0.0154 m.