Question

The vapour pressure of 5% aqueous solution of a non volatile organic substance at 373k is 745mm .Calculate the molar mass of the solute

Answer 1

Answer:

5 % aqueous solution of the solute means that 5g of the solute are present in 100 g of the solution

(i.e) Weight of Solute (w2)=5g

Weight of solution =100 g

weight of solvent (w1)=100−5=95g

Further as the solution in aqueous , it means that the solvent is water and we know that

Vapour pressure of pure water at 373K(p0)=760mm

Vapour pressure of solution at 373.k(Ps)=745mm

Molecular mass of solvent (water ).M1=18

Molecular mass of solute M2 = to be calculated

Using the formula for dilute solution ,

M2=w2×M1(p0)wt(po−Ps)

M2=5×18×76095×(760−745)

M2=684001425=48

Explanation:

HOPE I MAY HELP U ,MARK NE BRAINLIST