According to Graham's observations, which particles of gas move faster?

Graham's law of effusion and diffusion suggests that the rate at which gas particles escape through a small opening is inversely proportional to the square root of their molar mass. This means that lighter particles, which have lower molar mass, will move faster than heavier particles when all other conditions are equal.

In this context, H2 (hydrogen gas) is significantly lighter than CO2 (carbon dioxide), SO2 (sulfur dioxide), and O2 (oxygen). The low molar mass of hydrogen allows its particles to attain higher velocities, leading to quicker movement compared to the heavier gas particles mentioned in the other choices. Thus, for the question about which gas particles move faster, relatively light particles such as H2 are indeed the correct answer, reflecting the principles established by Graham in his research on gas behavior.