To 250 g of a 10% sulfuric acid solution was added 120 g of a 20% sulfuric acid solution.

To 250 g of a 10% sulfuric acid solution was added 120 g of a 20% sulfuric acid solution. What concentration was the solution obtained.

Given:

m (first solution) = 250 g

w% (H2SO4) = 10%

m (second solution) = 120 g

w% (H2SO4) = 20%

Find:

% (H2SO4 in the final solution) -?

Solution:

1) Find the mass of acid in both solutions:

m1 (H2SO4) = 250 g * 0.1 = 25 g;

m2 (H2SO4) = 120 g * 0.2 = 24 g;

2) Find the total mass of acid in the final solution:

m (H2SO4) = 24 g + 25 g = 49 g;

3) Find the mass of the solution after draining:

m (solution) = 250 g + 120 g = 370 g;

4) Find the mass fraction of sulfuric acid in the resulting solution:

w% (H2SO4) = m (H2SO4): m (solution) * 100% = 49 g: 370 g * 100% = 13.24%.

Answer: w% (H2SO4) = 13.24%.