WBJEE 2024 Physics & Chemistry Paper

In thermodynamics, a spontaneous reaction is one that occurs naturally without needing to be driven by external forces. The spontaneity of a reaction is primarily determined by the Gibbs free energy change $(\Delta G)$. For a reaction to be spontaneous, the Gibbs free energy change must be negative (i.e., $\Delta G < 0$ ). The Gibbs free energy is related to the enthalpy change $(\Delta H)$ and the entropy change $(\Delta S)$ by the equation:$\Delta G = \Delta H - T \Delta S$where $T$ is the absolute temperature in Kelvin. For polymerization reactions, typically they involve the formation of long-chain molecules from smaller monomer units. During this process: Enthalpy Change $(\Delta H)$ : Generally, polymerization reactions are exothermic (release heat), so $\Delta H$ is often negative.Entropy Change $(\Delta S)$ : Polymerization leads to a decrease in randomness since individual monomers form a more ordered polymer. Therefore, $\Delta S$ is usually negative.Given that a spontaneous reaction requires $\Delta G < 0$, and considering the typical characteristics of polynomial reactions, the correct conditions should be:$\; \Delta G < 0$$\; \Delta H < 0$$\; \Delta S < 0$So, option A $\Delta G < 0, \Delta H < 0, \Delta S < 0$ is the correct one for a spontaneous polymerization reaction.