How much water should be added to 10 mL of 18% achohol solution to reduce the concentration to 5%? Why?

Question

How much water should be added to 10 mL of 18% achohol solution to reduce the concentration to 5%? Why?

Answer 1

Hi Nick,

 

10 mL = 18% alcohol and 82% water

therefore:
solution = 1.8 mL alcohol and 8.2 mL water

 

Dilution formula of concentration:
C1 x V1 = C2 x V2  (where C is concentration and V is volume)

.18(10) = .05(V2)

 

1.8/.05 = V2

V2 = 36 ml

therefore

36 mL = 5% alcohol and 95% water

solution = 1.8 mL alcohol and 34.2 mL water

 

Water added = 34.2 - 8.2 = 26 mL