Question

If the elevation in the boiling point of a solution of 10 g of solute (molecular mass = 100 g/mol) in 100 g of water is ∆T_b, the ebullioscopic constant of water is ____________.

Options

• 10

• 100 T_b

• ∆T_b

• `(∆"T"_"b")/10`

Answer 1

If the elevation in the boiling point of a solution of 10 g of solute (molecular mass = 100 g/mol) in 100 g of water is ∆T_b, the ebullioscopic constant of water is ∆T_b.

Explanation:

Mass of solute = W₂ = 10 g = 10 g

Molecular weight of the solute = M₂ = 100 g/mol

Mass of the solvent = W₁ = 100 g

Elevation in boiling point = ∆T_b

Ebullioscopic constant of water = K_b

∆T_b = `("K"_"b" xx "W"_2)/("M"_2 xx "W"_1) = ("K"_"b" xx 10  "g" xx 1000  "g kg"^-1)/(100  "g mol"^-1 xx 100  "g")` = K_b