What mass of solid sodium hydroxide should be taken to prepare 200 g of a 25% solution.

Let’s find the weight of the alkali.

M alkali = 200 x 0.25 = 50 grams;

Similarly, we find the weight of the solvent (water).

(In the calculations, we take the density of water equal to 1 gram / cm3).

M water (solvent) = 200 x 0.75 = 150 grams = 150 ml;

Let’s check. To do this, add the masses of the components of the solution and get the mass of the required solution.

50 + 150 = 200;