Question

A 90% acid solution is mixed with a 97% acid solution to obtain 21 litres of a 95%

Answer 1

V1 = volume of 90% solution

V2 = volume of 97% solution

Volume of solution = V1 + v2 = 21 L 

Concentration = 95% = (V1 * 90% + V2 * 97%) / 21 

so  21 * 95 = 90 V1 + 97 V2

                   = 90 V1 + 97 (21 - V1) = 97 * 21 - 7 V1

So     V1 = 6 L   and V2 = 15 L

Answer 2

Answer:

refer attachment above please