Question

What amount of pure acid must be added to 600 mL of a 20% acid solution to produce a 50% acid solution?

Answer 1

180 mL

Explanation:

20% of the 600 mL is going to be pure acid so to make it 50% you would need 30% more pure acid.

50% of 600 is 300, 300 minus 120 is 180 meaning the remaining 30% is 180 mL