Some Basic Concepts of Chemistry - Result Question 40 — JEE PYQ Chapterwise

Answer:

Correct Answer: 53. $\left(9.9 \times 10^{-3}\right)$

Solution:

53. Moles of sugar=34.2/342=0.1 Moles of water in syrup=214.2-34.2=180 g Therefore, (i) Molality=Moles of solute/Weight of Solvent (kg) × 1000 =0.1/0.18 × 1000=5.56

$\text { (ii) Mole fraction of sugar } \begin{aligned} & =\frac{\text { Mole of sugar }}{\text { Mole of sugar }+ \text { Mole of water }} \\ & =\frac{0.1}{0.1+10}=9.9 \times 10^{-3} \end{aligned}$