Question

What is the boiling point of a solution of ethanol, C2H5OH and sugar that contains 20.0 g of the sugar in 250 g of water

Answer 1

Boiling point of ethanol is 78.5
`^(0)C`

`K_(b)` of ethanol is
`1.22^(0)C/m`

The relationship between boiling point elevation of a solution and molality can be represented as,

Δ
`T_(b) = K_(b) m`

Molality of the solution (m) =
`20.0 g C_(12)H_(22)O_(11) * (1 mol C_(12)H_(22)O_(11))/(342.3 gC_(12)H_(22)O_(11)) *(1)/(250 g solvent) * (1000 g)/(1 kg)`

= 0.234 m

`T_(b)(solution) - T_(b)(ethanol) = 1.22^(0)C/m`
`* ( 0.234 m)`

`T_(b)(solution) - 73.5 ^(0)C = 1.22^(0)C/m ( 0.234m)`

`T_(b)(solution) = 73.8^(0)C`

Therefore the boiling point of solution will be 73.8
`^(0)C`