Diffusion rate follows Graham's law and increases with temperature

Steps:

• Apply Graham's law: diffusion rate ∝ 1/√(molar mass), so lighter gases diffuse faster.
• Higher temperature increases molecular kinetic energy, speeding up diffusion for all gases.
• Molar mass of neon (20 g/mol) is less than carbon dioxide (44 g/mol), favoring neon.
• At 25°C, neon has both lowest mass and highest temperature, maximizing rate.

Why D is correct:

• Neon at 25°C combines lowest molar mass (fastest per Graham's law) with highest temperature (highest kinetic energy).

Why the others are wrong:

• A: Carbon dioxide's higher mass slows diffusion; 0°C further reduces rate.
• B: Higher mass than neon outweighs temperature advantage over A.
• C: Neon diffuses faster than CO2 options but 0°C limits speed compared to D.

Final answer: D