Solutions - Intext Questions and Answer - class 12 chemistry

Solution:

Given, % of benzene by mass = 30%

Thus, % of solvent (carbon tetrachloride) = 70%

Mole fraction of benzene in the given solution = ?

This means, 30g of benzene (C₆ H ₆) is dissolved in 70 g of CCl ₄

Now, Molecular mass of benzene (C₆ H₆ ) = (12 x 6) + (1 x 6) = 78 g mol ^{– 1}

Molecular mass of carbon tetrachloride (CCl₄ ) = 12 + (35.5 x 4 ) = 154 g mol ^{– 1}

Therefore, Number of moles of C ₆H ₆

And, number of moles of CCl₄

Thus, mole fraction of benzene in the given solution

Thus, mole fraction of benzene in the given solution = 0.457