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

To find: How much ml of solution taken from 50% and 80%.

Proof:

Let's assume that x be taken from 50% solution , (100-x) be taken from 80% solution.

From the above we have,

x + (100-x) = 100   ( ∵total solution is 100ml)

Now,

50% * x + 80% * (100-x) = 68% * 100

=>1/2 x + 4/5 (100-x) = 17/25 * 100

=>0.5 x + 80 - 0.8 x = 68

=> - 0.3 x = - 12   ( Cancelling the negative sign on both side)

=> x = 40

We have assumed x be taken from 50% solution

=> x = 40

and

(100-x) be taken from 80% solution

=> (100 - 40) = 60

Hence, 40ml is taken from 50% Solution ,

            60ml is taken from 80% Solution