Question

You purchased a 12 M concentrated solution of hydrochloric acid from Fisher Scientific. Explain how you would prepare 500 mL of 2.0 M HCl from the concentrated solution. If you are doing a dilution of concentrated acids, then do you add the acid to the water or the other way around. Why is the diluted acid solution made in this manner?

Answer 1

V1S1=V2S2

500 ml x 2 M = V2 x 12 M

V2= 500 ml x 2 M/12M = 83.33 ml

STEPS:

Take 83.33 ml conc. 12M HCl in 500 ml volumetric flask through measuring cylinder.

Make up the volume upto 500 ml mark using water as a solvent through another measuring cylinder.

Since water is in large excess, it can be added at the end for HCl.

Else add few ml water (250 ml or more ) in volumetric flask then add acid and make up the rest volume with water to avoid explosion which will be the case of H2SO4. Be careful about H2SO4 preparation.

Else slowly add dropwise conc. HCl to the water in a beaker or volumetric flask to avoid explosion and glass rod to make homogeneous solution.