Answer:
Helium
Step-by-step explanation:
Scottish physicist Thomas Graham formulated a law known as Graham's law of effusion in 1848. He conducted an experiment and found the relationship between the rate of effusion of a gas and its molar mass as:
where,
r is the rate of effusion of a gas
M is the molar mass of the gas.
And for two gases taking different rate of effusion as r₁ and r₂ to effuse, the formula is:
Since, Helium has a lower molecular mass as compared to that of neon. So, Helium will escape faster through the pinhole.