Question

Find mole fraction of $NaOH$ in its $10\%$ aqueous solution.

Answer 1

NaOH solution is prepared in water.

Molar mass of $NaOH=40g$

Mass of $NaOH=10g$

Molar mass of water = 18 g

Given mass of water = 90 g

Number of moles of $NaOH=\frac{10}{40}=0.25moles$

Number of moles of $H_{2}O=\frac{90}{18}=5moles$

Mole fraction of $NaOH=\frac{0.25}{0.25+5}=0.047$