In one liter of water, 2 mol of sodium hydroxide was dissolved. Determine the mass fraction of sodium hydroxide in the solution.

The mass fraction is taken to mean the ratio of the mass of the solute to the mass of the solution. To find the mass fraction of caustic soda in a solution, it must be converted into units of mass (in grams). Let’s calculate the mass of sodium hydroxide.

m = n * M, where n is the amount of substance, M is the molar mass. M (NaOH) = 40 g / mol

m = 2 * 40 = 80 g.

The mass of a liter of water is found by multiplying the volume by the density. The density of water is roughly 1000 g / liter, so the mass of 1 liter of water = 1000 g.

Now let’s find the mass of the resulting solution:

m (solution) = 1000 + 80 = 1080 g.

Find the mass fraction of sodium hydroxide:

w = 80/1080 = 0.074

Answer: mass fraction of NaOH in solution = 0.074