ANS:C -

The diffusivity (D) in a binary gas mixture is related to the pressure (P) by the Stokes-Einstein relation, which states that the diffusivity is inversely proportional to the pressure. Mathematically, this relationship can be expressed as: 𝐷∝1𝑃D∝P1​ Where:

• 𝐷D is the diffusivity of the gas mixture,
• 𝑃P is the pressure.

This relationship implies that as the pressure of the gas mixture increases, the diffusivity decreases, and vice versa. It's important to note that this relationship holds under certain conditions, such as when the gas mixture behaves ideally and the Stokes-Einstein relation is applicable.