Question

The doctor ordered 750ml of a 15 percent solution. the stock solution is 50 percent. how much stock solution and diluent are needed?

Answer 1

The doctor required a 15% 750mL solution. To lower the concentration of the solution, you have to add more diluting liquid. 

750mL * 0.15 = 112.5mL. This 112.5mL signifies the pure chemical or compound in the solution. This 112.5mL can be taken from the stock solution.

112.5 * 2 = 250mL of stock solution would be needed and 500 mL of the diluting agent should be added. Adding the two together would result to a 750mL solution of 15% concentration.