Question

You can purchase hydrochloric acid in a concentrated form that is 37.0% HCl by mass and that has a density of 1.20 g/mL. Describe exactly how to prepare 2.85 L of 0.500 M HCl from the concentrated solution.

Answer 1

Answer:

We take 117mL of the 37.0% by mass solution of HCl, and we complete with water to a final volume of 2.85L

Explanation:

First of all, we calculate the molarity of concentrated solution.

37% by mass means that 37 g of solute are contained in 100 g of solution.

So density which apply for solution, help us to determine the volume of solution.

Solution density = Solution mass / Solution volume

1.20 g/mL = 100 g / Solution volume → 100 g / 1.20 g/mL = 83.3mL

Then 37 g of HCl are contained in 83.3 mL. Let's calculate the molarity (mol/L)

37 g / 37.45 g/mol = 1.01 mol

83.3 mL . 1 L/1000mL = 0.0833 L

1.01 mol / 0.0833L = 12.2 M

Let's apply the dilution formula

Conc. M . Conc. volume = Diluted M . diluted volume

12.2 M . Concentrated volume = 0.5 M . 2.85L  

Concentrated volume = ( 0.5 M . 2.85L) / 12.2 M → 0.1168 L ≅ 0.117L