Question

$0.24$ g of a volatile substance, upon vaporization, gives $45$ ml of vapour at STP. The vapour density of the substance is:

• A. $5.993$
• B. $59.73$
• C. $95.39$
• D. $95.93$

Answer 1

The correct option is B $59.73$

$0.24$ g of a volatile substance gives $45$ ml at STP.

$22400$ ml (or $1$ mole) at STP will give $\frac{0.24}{45}\times 22400=119.47$ g.

The vapour density is one half the molecular weight.

Vapour density = $\frac{\text{Mol. wt.}}{2}=\frac{119.47}{2}=59.73$.

Hence, the correct option is $\text{B}$