Question

20. Acid Mixture Bill Charlson needs 10% hydrochloric acid

for a chemistry experiment. How much 5% acid should he
mix with 60 milliliters of 20% acid to obtain a 10% solution?

Answer 1

5% more to the mixture

Answer 2

120 ml

Explanation:

Let x ml of 5% acid should mix with 60 milliliters of 20% acid to obtain a 10% solution,

Thus, the quantity of resultant mixture = ( x + 60 ) ml,

Also,

Acid in x ml 5% acid + Acid in x ml 5% acid = acid in 10% resultant solution,

5% of x + 20% of 60 = 10% of ( x + 60)

`(5x)/(100)+(20* 60)/(100)=(10* (x+60))/(100)`

`5x + 1200 = 10x + 600`

`5x - 10x = 600 - 1200`

`-5x = -600`

`\implies x = (-600)/(-5)=120`

Hence, 120 ml of 5% acid should be mixed.