Mixed 70 g of a 30% Naoh solution and 30 g of a 5% solution of the same hydroxide.

Mixed 70 g of a 30% Naoh solution and 30 g of a 5% solution of the same hydroxide. Calculate the mass fraction of Naoh in the resulting solution.

The weight of the resulting solution will be equal to the sum of the masses of the two initial solutions.

M = 70 + 30 = 100 grams;

The mass of alkali in the first solution is 70 x 0.3 = 21 grams;

The mass of alkali in the second solution is 30 x 0.05 = 1.5 grams;

The mass of alkali in the resulting solution will be equal to 21 + 1.5 = 22.5 grams;

The alkali concentration in the new solution will be 22.5 / 100 = 0.225 = 22.5%;