Question

A chemist has two solutions of hydrochloric acid in stock. One is 50% solution and the

other is 80% solution. How much of each should be used to obtain 100ml of a 68%

solution.

Answer 1

equation of total mass

x + y = 100

equation for hydrochloric acid

0.5x + 0.8y = 0.68 x 100.

so,

x + y = 100

y = 100 - x putting this eq in the other equation

0.80X+.50(100-X)=.68 x 100

0.80X+ 50- 0.50X=68

0.30X=68-50

0.30X=18

x=18/0.30

x =60 ml of 80% solution is used

100-60=40 ml of 50% solution is used