pure acid is to be added to a 5% acid solution to obtain 95L of 16% solution. what amounts of each should be used?

Question

how many liters of 100% pure acid should be used to make the solution?

Answer 1

A=amount of 100% acid and X=amount of 5% acid solution. A+X=95 (equating amounts of liquid) and A+X/20=16/100*95=16*19/20 (equating amounts of acid present in each liquid).

Multiply last equation through by 20: 20A+X=304. Subtract first equation: 19A=304-95=209, A=209/19=11L and X=95-11=84L. So 11L of pure acid needs to be added to 84L of 5% acid solution to produce 95L of 16% acid solution.