According to Le Chatelier’s principle, if the dynamic equilibrium of a system is disturbed by any change in the conditions of the system then the equilibrium will adjust itself in such a way that new equilibrium moves to counteract the change.
Hence, when the concentration of reactants is doubled in a chemical reaction that was in equilibrium then the equilibrium shifts to the right to favor the formation of products.
The answer is B. You are correct.
According to
Graham's Law of Diffusion,"the rates of diffusion of two gases are inversely proportional to the square root of their Molar masses or Densities at the same pressure and temperature".
r₁ / r₂ =

Where,
r₁ = Rate of Helium
r₂ = Rate of Oxygen
M₂ = Molar mass of Oxygen = 32 g/mol
M₁ = Molar mass of Fluorine = 4 g/mol
Putting values,
r₁ / r₂ =

r₁ / r₂ =

r₁ / r₂ =
2.82
Result:
Helium gas effuses
2.82 times faster than Oxygen gas.