Question

5 gram each of the following gases at ${87}^{\circ }C$ and $750mm$ pressure is taken. Which of them will have the least volume?

• A. $HF$
• B. $HCl$
• C. $HBr$
• D. $HI$

Answer 1

The correct option is D $HI$

From Ideal gas law,

$PV=\frac{Weight}{Molarmass}\times RT$

The gas with maximum molecular weight will have minimum volume.

$HI$ has the maximum molecular weight, hence has the least volume.