Question

Calculate the molarity of a 10.0% (by mass) aqueous solution of hydrochloric acid.

Answer 1

The question is incomplete,the complete question :

Calculate the molality of a 10.0% (by mass) aqueous solution of hydrochloric acid:

a) 0.274 m

b) 2.74 m

c) 3.05 m

d) 4.33 m

e) the density of the solution is needed to solve the problem

Answer:

The molality of a 10.0% (by mass) aqueous solution of hydrochloric acid is 3.05 mol/kg.

Explanation:

10.0% (by mass) aqueous solution of hydrochloric acid.

10 grams of HCl is present in 100 g of solution.

Mass of HCl = 10 g

Mass of solution = 100 g

Mass of solution = Mass of solute + Mass of water

Mass of water = 100 g - 10 g = 90 g

Moles of HCl = $\frac{10 g}{36.5 g/mol}=0.2740 mol$

Mass of water in kilograms = 0.090 kg

Molality = $\frac{0.2740 mol}{0.090 kg}=3.05 mol/kg$

The molality of a 10.0% (by mass) aqueous solution of hydrochloric acid is 3.05 mol/kg.