Question 564714: how many gallons of hydrochloric acid must be added to 12 gallons of a 30% solution to obtain a 40% solution? Answer by Maths68(1474) (Show Source):
You can put this solution on YOUR website! Solution A
Amount = 12 gallons
Concentration =30% =0.3
Solution B
Amount = x
Concentration =100% = 1 (Pure Hydrochloric acid)
Resultant Solution
Amount =12+x
Concentration =40%=0.4
[Amount Solution A * Concentration A] + [Amount Solution B * Concentration of B] = Amount of Resultant * Concentration of resultant
12*0.3 + x*1 = (12+x)*0.4
3.6+x=4.8+0.4x
x-0.4x=4.8-3.6
0.6x=1.2
0.6x/0.6=1.2/0.6
x=2
2 gallons of hydrochloric acid (pure) must be added to 12 gallons of a 30% solution to obtain a 40% solution.