Q12.8: NCERT Physics - Part 2 KINETIC THEORY 12.8 Solution: Three vessels of equal capacity have gases at the same…

**Answer:** Yes, equal number of molecules. No, $v_{rms}$ is not the same. Neon has the largest $v_{rms}$. **Step-by-Step Explanation:** Since the vessels have the same volume, pressure, and temperature, by Avogadro's law they contain equal number of molecules. The root mean square speed: Since $k$ and $T$ are the same for all gases, $v_{rms} \propto 1/\sqrt{m}$, where $m$ is the mass of one molecule. Among neon (atomic mass � 20 u), chlorine (molecular mass � 70 u), and uranium hexafluoride (molecular mass � 352 u), neon has the smallest molecular mass, so it has the largest $v_{rms}$ [citation:19].