180 grams of 15% sodium hydroxide solution was dissolved another 20 grams of alkali.

180 grams of 15% sodium hydroxide solution was dissolved another 20 grams of alkali. Calculate the mass fraction of the alkali.

This problem can be solved mathematically as percentage problems are solved. So we need to determine how much alkali was in the original solution. The mass of sodium hydroxide is equal.

0.15 x 180 = 27 g.

Then we determine the total mass of the solution.

180 + 20 = 200 g.

Determine the mass of alkali in the solution after adding 20 grams of alkali.

This will.

27 + 20 = 47 g.

the mass fraction of alkali in the solution after addition is equal to.

47: 200 = 0.235 A as a percentage, this will be 23.5% (we determined the percentage by multiplying the mass fraction by 100%).