For a silute solution conatining `2.5 g` of a non-volatile non-electrolyte solute in 100g of water, the elevation in boiling point at 1 atm pressure is `2^(@)C`. Assuming concentration of solute is much lower than the concentration (take `K_(b) = 0.76 K kg mol^(-1))`

Options

A. 724
B. 740
C. 736
D. 718

Answer

A

Explanation

`DeltaT_(b) = K_(b) xx m` ...(i)
`(760 -P_(s))/(760) = m xx (18)/(1000)` [for a dilute solution] ..(ii)
By eq.(i)/(ii)
`(2)/(760 -P_(s)) xx 760 =(0.76)/(18) xx 1000`
`P_(s) = 724`