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Assertion : During adsorption, DeltaG, D...

Assertion : During adsorption, `DeltaG, DeltaH and DeltaS` decrease i.e., their values become negative.
Reason : Adsorption is a spontaneous process. Randomness or disorder decreases during adsorption.

A

Statement -1 is True, Statement -2 is True, Statement -2 is a correct explanation for Statement - 1

B

Statement -1 is True, Statement -2 is True, Statement -2 is NOT a correct explanation for Statement - 2

C

Statement - 1 is True, Statement - 2 is False

D

Statement - 1 is False, Statement - 2 is True

Text Solution

AI Generated Solution

The correct Answer is:
To analyze the assertion and reason provided in the question, we can break it down step by step: ### Step 1: Understanding the Assertion The assertion states that during adsorption, the values of ΔG (Gibbs free energy change), ΔH (enthalpy change), and ΔS (entropy change) decrease, meaning they become negative. - **ΔH (Enthalpy Change)**: Adsorption is typically an exothermic process, which means it releases heat. Therefore, ΔH is negative during adsorption. - **ΔG (Gibbs Free Energy Change)**: For a process to be spontaneous, ΔG must be negative. Since adsorption is spontaneous, ΔG is also negative. - **ΔS (Entropy Change)**: During adsorption, a gas or solute molecules adhere to a surface, leading to a more ordered state. This results in a decrease in randomness or disorder, hence ΔS is negative. ### Conclusion for Step 1: Thus, the assertion that ΔG, ΔH, and ΔS decrease (become negative) during adsorption is correct. ### Step 2: Understanding the Reason The reason states that adsorption is a spontaneous process and that randomness or disorder decreases during adsorption. - **Spontaneity**: As mentioned, adsorption is indeed a spontaneous process, which is indicated by the negative ΔG. - **Randomness/Disorder**: When molecules adsorb onto a surface, they lose some freedom of movement, leading to a decrease in entropy (randomness). Therefore, the statement about randomness or disorder decreasing is also correct. ### Conclusion for Step 2: Both parts of the reason are correct: adsorption is spontaneous, and it leads to a decrease in randomness or disorder. ### Final Conclusion: Since both the assertion and the reason are correct, we can conclude that the assertion is true and the reason correctly explains the assertion.
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Knowledge Check

  • Assertion : Physical adsorption increases with increase in temperature. Reason : Physical adsorption is an endothermic process.

    A
    If both assertion and reason are true and reason is the correct explanation of assertion.
    B
    If both assertion and reason are true but reason is not the correct explanation of assertion
    C
    If assertion is true but reason is false
    D
    if both assertion and reason are false

  • Fill in the blanks by putting appropriate choices. During adsorption there is _______ in enthalpy and _______ in the entropy of a system by adsorption is a spontaneous process and thus DeltaG must be ________. Rate of physisorption ________ with increase in pressure.

    A
    decrease, decrease, negative , increase
    B
    increase, increase , positive , decrease
    C
    decrease, increase, negative , decrease
    D
    increase, decrease, positive , increase

  • Assertion : If both DeltaH^(@) and DeltaS^(@) are positive then reaction will be spontaneous at high temperature. Reason : All processes with positive entropy change are spontaneous.

    A
    If both assertion and reason are true and reason is the correct explanation of assertion.
    B
    If both assertion and reason are true but reason is not the correct explanation of assertion
    C
    If assertion is true but reason is false.
    D
    If both assertion and reason are false.