To a solution of 20% hydroxide na weighing 200 g was added 20 g of water.

To a solution of 20% hydroxide na weighing 200 g was added 20 g of water. Find the volume fraction of Naoh in the resulting solution.

Find the mass of the mass of sodium hydroxide in the solution. We write down the solution.

W = m r.v / m r-ra * 100%.

m r.v = 200 * 0.2 = 40 g.

Then we find the mass of the entire solution.

m solution total = m solution + m H2O.

m solution total = 200 g + 20 g = 220 g.

Next, we find the mass fraction of sodium hydroxide in the resulting solution. We write down the resulting solution.

W (NaOH) = 40 g / 220 g * 100% = 18.2%.

This means that the mass fraction of sodium hydroxide in the resulting solution is 18.2 percent.

Answer: the mass fraction of sodium hydroxide is 18.2%.