During the adsorption of gas on the surface of solid, which of the following is true?
During the adsorption of gas on the surface of solid, which of the following is true?
ΔG < O, ΔH < O, ΔS > O
ΔG < O, ΔH < O, ΔS < O
ΔG > O, ΔH < O, ΔS < O
ΔG < O, ΔH > O, ΔS < O
The Correct Option is B
Solution and Explanation
To solve the problem, we need to determine the correct thermodynamic changes (ΔG, ΔH, and ΔS) during the adsorption of a gas on the surface of a solid.
1. Understanding the Process of Adsorption:
Adsorption is the process where gas molecules adhere to the surface of a solid. This process typically occurs spontaneously under favorable conditions.
2. Analyzing the Thermodynamic Changes:
- ΔG (Gibbs Free Energy): For a process to be spontaneous, ΔG must be negative (ΔG < 0). In adsorption, the process is spontaneous, as the gas molecules are bound to the solid surface and stabilize.
- ΔH (Enthalpy Change): The adsorption process is usually exothermic, meaning heat is released as the gas molecules bind to the solid surface. Therefore, ΔH is negative (ΔH < 0).
- ΔS (Entropy Change): During adsorption, gas molecules are restricted to the surface of the solid, leading to a decrease in randomness or disorder. Therefore, ΔS is negative (ΔS < 0).
3. Conclusion:
In the adsorption of a gas on the surface of a solid, the thermodynamic changes are as follows:
ΔG < 0 (spontaneous), ΔH < 0 (exothermic), and ΔS < 0 (decrease in disorder).
Final Answer:
The correct answer is: ΔG < 0, ΔH < 0, ΔS < 0
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Concepts Used:
Surface Chemistry
The study of the chemical phenomena that occur at the interface of two surfaces which can be solid-liquid, solid-gas, solid-vacuum, liquid-gas, etc.
Read Also: Surface Chemistry
Applications of surface chemistry are:
Adsorption:
The process of attraction and aggregation of the molecules of a substance on the surface of a solid is known as adsorption. For Example, N2 adsorbs on the surface of activated charcoal
Two types of adsorption are:-
- Chemisorption: It is also known as Chemical Adsorption.
- Physisorption: It is also known as Physical Adsorption.
Corrosion:
The process through which the refined metals convert themselves into more stable compounds is known as corrosion.
Crystallisation:
The type of technique used in order to purify the substances to separate Solids from liquids is known as crystallisation.
Heterogeneous Catalysis:
The process wherein a catalyst is used in order to increase the rate of a chemical reaction is known as catalysis. The catalyst does not undergo any transformation and can be recovered in a chemically unchanged state.
There are two types of catalysis:-
- When the catalyst involved and the reacting substances are same states of matter or in the same phase, it is known as Homogeneous Catalysis.
- When the catalyst involved and the reacting substances are in different states of matter or different phases, it is known as Heterogeneous Catalysis.