MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

Entropy ( S) is a measure of randomness or disorder in a system. For dissolving sugar in water, solid sugar molecules break apart and mix with water, increasing the randomness. Thus, S > 0. For the adsorption of a gas on a solid surface, the gas molecules are restricted to the surface of the solid, which decreases their translational degrees of freedom. The randomness of the system decreases, leading to S For the reaction 2 NH _3(g) N _2(g) + 3 H _2(g), the number of gaseous moles increases from 2 to 4 ( n_g = 2). An increase in gaseous moles increases randomness, so S > 0. For the sublimation of dry ice, solid CO _2 converts into gaseous CO _2. Since gases are more disordered than solids, S > 0. Therefore, the only process with a negative S is the adsorption of a gas on a solid surface. Answer: Adsorption of a Gas on a Solid Surface