(a)
The boiling point of inert gases increases with increases in molecular weight due to increase in van der Waal’s forces.
$\because\$Xe has largest size, among inert gases.
$\therefore\$Xe has highest boiling point.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.