You have a large amount of 7.50M stock solution. You need 1.80L of 3.00M solution for an experiment. How would you prepare the desired solution without wasting any stock solution?

Answer 1

The easiest way to work the problem is to use the dilution formula of
c1v1 = c2v2
7.5*v1 = 3.00*1.80L
v1 = 3.00*1.80/7.5 = 0.72L or 720 mL of stock. However, do you have a 1.80 L volumetric flask? Probably not. So I would use a 2.0L volumetric flask and
7.5*v1 = 3.00*2
and v1 = about 800 mL. You would measure 800 mL of the stock, add to the 2.0 L volumetric flask, and add water to the mark on the flask.