making standard solution 1

Preparing a standard solution of 100cm3 of 0.5 mol dm-3 HCl from 2.0 mol dm-3 HCl stock.

Step 1: use the formula

Vs = Vf x CF/ CI

Step 2: definitions

Vs  volume of solution needed to be diluted to give the required concentration

Vf  the final volume required (100cm3)

CF   final concentration required (0.5 mol dm-3)

CI   initial concentration (2.0 mol dm-3)

Step 3: calculate the volume of solution needed to be diluted

Vs = 100 x 0.5/2.0

=cm3

So, to prepare a standard solution of 100cm3 of 0.4mol dm-3 HCl from 2.0 mol dm-3 HCl, you would measure out BBcm3 of 2.0 mol dm-3 HCl stock in a volumetric flask and make up the volume to 100cm3.