Determination of Entropy Change (S) for Each Process
To identify which process has a negative entropy change (S < 0),="" we="" need="" to="" analyze="" each="" option="" based="" on="" molecular="" disorder="" and="" energy="" dispersal.="" />
1. Adsorption
- When molecules adhere to a surface, such as activated charcoal, their freedom of movement is restricted.
- This leads to a decrease in disorder, hence a negative change in entropy (S < 0).="" />
2. Dissolution of NH4Cl in Water
- The dissolution of NH4Cl involves the dissociation of solid salt into ions.
- This increases the number of particles in solution, leading to greater disorder, thus S > 0.
3. H2 ⇌ 2H
- The dissociation of diatomic hydrogen into two hydrogen atoms increases the number of gas molecules.
- This process also increases disorder, indicating S > 0.
4. 2Na2CO3 + CO2 + H2O
- This reaction leads to the formation of sodium bicarbonate and involves gas evolution (CO2).
- The overall increase in the number of gaseous molecules results in higher disorder, so S > 0.
Conclusion
Among the listed processes, adsorption is the only one that exhibits a negative entropy change (S < 0)="" due="" to="" the="" restriction="" of="" molecular="" freedom="" and="" the="" reduction="" in="" randomness.="" 0)="" due="" to="" the="" restriction="" of="" molecular="" freedom="" and="" the="" reduction="" in="" />