Question

A solution is prepared by mixing 24 g of NaOH in 79.2 g of water. The mole fraction with respect to NaOH in the prepared solution is

Answer 1

Given info : A solution is prepared by mixing 24 g of NaOH in 79.2 g of water.

To find : the mole fraction with to NaOH in the prepared solution is ...

solution : mass of NaOH is 24g

molecular mass of NaOH = 40g/mol

∴ no of moles of NaOH = 24/40 = 0.6 mol

mass of water = 79.2 g

molecular mass of water = 18g/mol

∴ no of moles of water = 79.2/18 = 4.4 mol

now the mole fraction of NaOH = no of moles of NaOH/(no of moles of NaOH + no of moles of water)

= 0.4/(0.4 + 4.4) = 0.4/4.8 = 1/12 = 0.083

therefore the mole fraction of NaOH is 0.083 and the mole fraction of water is 1 - 0.083 = 0.917