Question

The weight of glucose dissolved in $100gm$ of water produce same lowering of vapour pressure as $1gm$ urea dissolved in $50gm$ of water at same temperature is

Answer 1

Answer: 6

Since same lowering in vapour pressure. Mole fractions of solutes should be equal.
$X_{\text{urea }}=X_{\text{glucose }}$
$\frac{\frac{1}{60}}{\frac{1}{60}+\frac{50}{18}}=\frac{\frac{w}{180}}{\frac{w}{180}+\frac{100}{18}}$
$\Rightarrow \frac{\frac{1}{60}}{\frac{50}{18}}=\frac{\frac{w}{180}}{\frac{100}{18}}$
For dilute solution $\Rightarrow w=6$ gm of glucose