Question

60 g CH₃COOH dissolved in 1 dm³ solvent, what is molality of solution?
(density= 1.25 g/cm³)

Options

• 0.8 m

• 0.4 m

• 0.2 m

• 0.6 m

Answer 1

0.8 m

Explanation:

Given,

Volume = 1dm³ = 10³ cm³

Density = 1.25 g/cm³

Mass = 60g

We know that, molahty (M) = `"Moles"/"Mass of solvents"`

∴ Moles = `"Given mass"/"Molar mass"`

`= (60 "g")/(60 "g"//"mol")`

= 1 mol

Molality (m) = `"Moles"/("Volume" xx "Density")`

m = `1/(1000 "cm"^3 xx 1.25 "g"//"cm"^3)`

`= 1/(1.25 "g" xx 10^3)`

`=> 1/(1.25 "kg")`

= 0.8 m