Question

WITHOUT USING THE DILUTIONS FORMULA what volume of concentrated hydrochloric acid (37.0% acid by weight, density=1.19g/ml) must be diluted to 500 ml to produce .300 M solution of the acid?

Answer 1

A solution's percent concentration by mass is defined as the mass of the solute, in your case hydrochloric acid, divided by the total mass of the solution, and multiplied by 100.

Percent concentration by mass is given by the mass of solute divided by the total mass of solution and multiplied by 100.

The stock solution of concentrated hydrochloric acid has a concentration of 37% by weight i.e., 37g of hydrochloric acid is present in every 100g of solution. For a 1L bottle of this solution whose density is 1.19 g/mL, it contains:

Now, we can determine the mass of this solution using its density,

We know that 37g of hydrochloric acid is present in 100g of the solution. Therefore, in 1190g of the solution

1 mole of hydrochloric acid contains 36.46g. Hence, 440.3g contains how many moles of hydrochloric acid. Therefore,

Hence the molarity of the stock solution must be:

Therefore, the volume of concentrated hydrochloric acid needed to be diluted for 500 mL of 0.300M solution of the acid is:

Therefore, 12.4 mL is required to make 500 mL of 0.300M hydrochloric acid from the stock solution.