Calculate the vapour pressure of a solution at `100^@C` containing `3`g of cane sugar in `33`g of water.(Atwt.C =`12`,h=`1`,O=`16`)

Options

A. `760mm`
B. `756.90mm`
C. `758.30mm`
D. None of these

Answer

B

Explanation

Vapour pressur of pure water (solvent) at `100^(@)C,P^(@)=760mm`.
Vapour pressure of solution,`p=?`
Wt. pf solvent ,W=33g
Wt. of solute,w=3g
Mol. Wt, of water `(H_(2)O),M=18`
Mol. Wt. of sugar `(C_(12)H_(22)O_(11)),`
`m=12xx12xx+22xx1+11xx16=342`
According to Raoult's law,
`(P^(@)-P)/(P)=(wM)/(Wm)`
`p=P^(0)-(wxxM)/(mxxw)xxP^(0)`
`p=760-(3xx18)/(342xx33)xx760`
`( :.P^(0) for H_(2)O=760mm)`