AIIMS 2019 Chemistry Entropy MCQ Question

In an isochoric process, the volume of the system remains constant, which means that any change in entropy (ΔS) must account for this fixed volume, leading to zero change in volume (V₂/V₁ = 1). Therefore, option A correctly states that the volume remains zero for an isochoric process, as it implies no expansion or compression occurs. Option B incorrectly states the specific heat capacity for a diatomic gas; it should be $C_v = \frac{5R}{2}$ only under certain conditions, not universally applicable. Option C miscalculates the entropy change by not considering the correct parameters for the specific process, leading to an incorrect numerical result.