What mass of alkali should be taken to prepare 50 g of a 16% solution?

The mass of the solution is 50 grams;

To find the mass of alkali, it is necessary to multiply its mass fraction by the mass of the solution.

m alkali = 50 x 0.16 = 8 grams;

To find the mass of water, it is necessary to subtract the mass of alkali from the mass of the solution:

m water = 50 – 8 = 42 grams;

Check: 8 + 42 = 50;