1.

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

Answer»

<P>724
740
736
718

Solution :`Delta T_(b)=K_(b)xx m`
`2=(0.76xx2.5//M)/(0.1)rArr M=9.5`
Since solute is present in less amount
`(P^(@)-P_(s))/(P^(@))=(n)/(N)`
`(760-P_(s))/(760)=(2.5//9.5)/(100//18)rArr P_(s)=724`


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