Question 16433
 chemist has 2.5 liters of a solution which is 70% acid. How much water should be added to obtain a 50% acid solution?
  qty.of solution = 2.5 l
   % acid in solution = 70
   hence qty.of acid in the solution = 2.5*70/100 = 1.75 l
   required percentage = 50
   let the water to be added = x l
    total qty.of solution = (2.5+x) l
    qty of acid =  same as before = 1.75 l
    % acid in the new solution = 1.75*100/(2.5+x) = 50 as given
        175= 50(2.5+x)
       2.5+x = 175/50 = 3.5
      x= 3.5 - 2.5 = 1  litre