Determine the volume of stock solution needed and the volume of diluent

Question

Prepare 30 L of formalin from a 100% stock solution. How much formalin is needed to make a 5% solutions? How much Diluent?

Answer 1

To make 30 L of 5% formalin solution from 100% stock solution, proceed as follows:

You can use the formula V1C1 = V2C2 where V1 and V2 are volumes of initial and final solutions and C1 and C2 are concentrations (%) of initial and final solutions. Thus, ...

(x L)(100%) = (30 L)(5%)

100x = 150

x = 150/100

x = 1.5

So, you need 1.5 L of the 100 % stock diluted to a final volume of 30 L, which means you must add 28.5 L of diluent. (Note: This assumes the volumes are additive)