QNEET-2024-Ch-10: NEET 2024 Chemistry - Class 11 NEET-2024-Ch-10 Solution: In which of the following processes entropy increases? A. A…

The concept of entropy in thermodynamics refers to the degree of randomness or disorder in a system. An increase in entropy is generally associated with processes in which disorder increases. Let's analyze each option listed: A. A liquid evaporates to vapour. During the evaporation of a liquid to form a vapour, the molecules of the substance move from a relatively ordered state (liquid) to a more disordered state (vapour). In a vapour, the molecules have more freedom of motion and are less confined than in a liquid. This transition from liquid to vapour increases the randomness or disorder of the system, hence, the entropy increases. B. Temperature of a crystalline solid lowered from 130   K to 0   K . Reducing the temperature of a crystalline solid generally decreases the entropy of the system. As the temperature decreases, the molecular motion within the solid becomes more restricted, leading to a decrease in randomness. At absolute zero ( 0   K ), the entropy is at its lowest possible value (ideally zero for a perfect crystal), as the molecular motion is minimized to only quantum mechanical vibrations. C. 2 NaHCO 3 ( s ) _ Na 2 CO 3 ( s ) + CO 2 ( g ) + H 2 O ( g ) In this chemical reaction, solid sodium bicarbonate decomposes to form solid sodium carbonate, carbon dioxide gas, and water vapor. The formation of gases from a solid significantly increases the entropy of the system because gases have much higher randomness due to their free molecular motion compared to solids. D. Cl 2 ( g ) _ 2 Cl ( g ) The dissociation of chlorine gas ( Cl 2 ) into atomic chlorine ( Cl ) represents a transition from a diatomic molecule to two separate atoms. This increases the number of particles in the gas phase, leading to increased randomness and disorder, hence, increasing the entropy. Conclusion: Based on our analysis, processes A, C, and D involve an increase in entropy, as they each lead to greater disorder or randomness in the system. Option B is incorrect as it wrongly includes lowering the temperature of a solid as increasing entropy. Therefore, the correct answer is: Option C : A, C and D