Question 486579
As usual, x = answer = added grams of H2O.
Currently 400*0.12 acid = 48g, 400 total.
After adding, strength = new acid (same) 48g / new total (400+x)g = 0.08
48 = 0.08 * (400+x)
x+400 = 48/0.08
x = 600-400 = 200g H2O