A common stain remover is sold in concentrated form as 3M sodium hypochlorite (NaOCl). You need to create 400 milliliters of a 0.5M solution of sodium hypochlorite to fill a spray bottle. What volume of 3M sodium hypochlorite is needed?

15.0 mL

66.7 mL

133 mL

167 mL

To solve this we use the equation,

M1V1 = M2V2

where M1 is the concentration of the stock solution, V1 is the volume of the stock solution, M2 is the concentration of the new solution and V2 is its volume.

3 M x V1 = 0.50 M x. 400 L

V1 = 0.07 L or 66.67 mL of the 3M sodium hypochlorite solution

The correct answer is the second option given.