Problem 22 - A Complete Resource Book in Chemistry for JEE Main

Question

The extent of adsorption of a gas on a solid depends upon (a) nature of gas (b) temperature of gas (c) pressure of gas (d) all of these

Step-by-Step Solution

Answer

The extent of adsorption depends on (d) all of these.

Step 1: Analyzing the Influence of Gas Nature

The nature of the gas affects how strongly it can adsorb onto a solid. Gases with higher polarity or gases that can form stronger interactions with the solid surface will typically adsorb more readily. Thus, the nature of gas is a factor in adsorption.

Step 2: Examining the Impact of Temperature on Adsorption

Temperature influences the extent of adsorption. Typically, adsorption is exothermic, so increasing temperature will decrease adsorption as it shifts the equilibrium towards desorption. Thus, temperature is a significant factor affecting adsorption.

Step 3: Considering the Role of Gas Pressure

Gas pressure also affects adsorption. Higher pressure means more gas molecules are available to interact with the solid, often increasing the extent of adsorption due to increased surface coverage. Therefore, pressure is a crucial factor in adsorption.

Step 4: Concluding with All Influences

From the analysis, it's clear that the extent of adsorption is affected by the combined effects of the nature of the gas, temperature, and pressure. All these factors are interdependent and collectively determine the extent to which a gas adsorbs onto a solid.

Key Concepts

Nature of Gas

The nature of a gas plays a crucial role in the adsorption process. This essentially refers to the inherent properties of the gas that make it interact with solids in a specific way. Certain gases have characteristics, such as polarity or the ability to form stronger bonds, which can enhance their adsorption onto solids.
- **Polarity**: Gases with higher polarity are more likely to adsorb well because they can engage in stronger interactions with the surface of a solid.
- **Interaction Strength**: Some gases naturally form stronger bonds with solid surfaces, enhancing their adsorption capability.
So, when considering adsorption, identifying the adhesive nature of gas to solid surfaces is key. Understanding these interactions is important for optimizing conditions in industrial applications where adsorption is crucial.

Temperature Effects

Temperature significantly impacts the extent of gas adsorption on a solid. Usually, adsorption is an exothermic process, meaning it releases heat. Thus, the following happens as temperature changes:
- **Increased Temperature**: When temperature rises, the equilibrium may shift towards desorption. This is because higher heat provides energy for the adsorbed gas molecules, facilitating their escape from the surface. - **Decreased Temperature**: On the flip side, lowering the temperature often favors the adsorption process. It reduces the kinetic energy of molecules, causing them to 'stick' to the solid surface more effectively.
Overall, understanding how temperature affects adsorption can help in controlling and maximizing this process where needed.

Pressure Effects

Pressure plays an equally vital role in the process of gas adsorption. High pressure increases the number of gas molecules in a given space, thus intensifying their interactions with the solid surface.
Here is how pressure affects adsorption:
- **High Pressure**: More gas molecules are compacted against the solid, increasing the likelihood of adsorption as the surface becomes more densely populated.
- **Low Pressure**: With fewer molecules pressing down on the surface, the extent of adsorption is generally reduced. These effects mean that manipulating pressure is an effective way to control the adsorption process, especially in industrial settings where efficiency is key.