Question

Calculate the mole fraction of NaOH and water in a solution formed by dissolving 4 gm of NaOH in 180 gm of water

Answer 1

Answer:-

Given:

Mass of NaOH (m) = 4 g

Molar mass of NaOH (M) = 23 + 16 + 1 = 40 g/mol.

Mass of water (m) = 180 g

Molar mass of water (M) = 2(1) + 16 = 18 g/mol.

We know that,

Number of moles (n) = Mass of the compound/Molar mass

→ Number of moles of NaOH = 4/40 = (1/10) mol

Similarly,

Number of moles of H2O (Water) = 180/18 = 10 mol

Mole Fraction of a compound (Xa) = n(a)/(n(a) + n(b) )

→ Mole Fraction of NaOH = (1/10) / (1/10 + 10)

→ X(NaOH) = (1/10) / [ (1 + 100) / 10 ]

→ X(NaOH) = (0.1) * (10/101)

→ X(NaOH) = 1/101

→ X(NaOH) = 0.009