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Assertion (A). Spontaneous process is an...

Assertion (A). Spontaneous process is an irreversible process and may be reversed by some external agency.
Reason (R). Decrease in enthalpy is a contributory factor for spontaneity

A

Both A and R are true and R is the correct explanation of A

B

Both A and R are true but R is not the correct explanation of A

C

A is true but R is false

D

A is false but R is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze both the assertion (A) and the reason (R) provided. ### Step 1: Analyze the Assertion (A) The assertion states: "Spontaneous process is an irreversible process and may be reversed by some external agency." - A spontaneous process is typically defined as a process that occurs naturally without needing to be driven by an external force. - Most spontaneous processes are indeed irreversible under normal conditions, meaning they cannot simply be reversed without some form of intervention or external influence. - However, the statement that they "may be reversed by some external agency" is misleading. While some spontaneous processes can be reversed, it is not a general characteristic of all spontaneous processes. ### Step 2: Analyze the Reason (R) The reason states: "Decrease in enthalpy is a contributory factor for spontaneity." - The spontaneity of a process is often determined by the Gibbs free energy change (ΔG). The relationship is given by the equation: \[ \Delta G = \Delta H - T \Delta S \] - For a process to be spontaneous, ΔG must be less than zero (ΔG < 0). - A decrease in enthalpy (ΔH < 0) can indeed contribute to a negative ΔG, making the process spontaneous. However, it is not the only factor; the entropy change (ΔS) and the temperature (T) also play significant roles. ### Step 3: Conclusion - Both the assertion and the reason are true statements in their own right. - However, the reason does not correctly explain the assertion because the assertion's claim about reversibility is not universally applicable to all spontaneous processes. ### Final Answer The correct answer is that both the assertion and reason are true, but the reason is not the correct explanation for the assertion. ---
To solve the question, we need to analyze both the assertion (A) and the reason (R) provided. ### Step 1: Analyze the Assertion (A) The assertion states: "Spontaneous process is an irreversible process and may be reversed by some external agency." - A spontaneous process is typically defined as a process that occurs naturally without needing to be driven by an external force. - Most spontaneous processes are indeed irreversible under normal conditions, meaning they cannot simply be reversed without some form of intervention or external influence. - However, the statement that they "may be reversed by some external agency" is misleading. While some spontaneous processes can be reversed, it is not a general characteristic of all spontaneous processes. ...
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Knowledge Check

  • Assertion : All spontaneous processes are thermodynamically irreversible. Reason : In a reversible isothermal process, there is no net change in entropy.

    A
    If both Assertion and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion.
    B
    If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion.
    C
    If Assertion is CORRECT but Reason is INCORRECT.
    D
    If Assertion is INCORRECT but Reason is CORRECT.

  • Assertion : An exothermic process which is non-spontaneous at high temperature may become spontaneous at low temperature. Reason : Spontaneous process is an irreversible process and may be reversed by some external agency.

    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.

  • Assertion: Thermodynamics process in nature are irreversible. Reason: Dissipative effects cannot be eliminated.

    A
    Both assertion and reason are true and reason is the correct explanation of assertion
    B
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    C
    Assertion is true but reason is false
    D
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    Assertion (A): The thermodynamic factor which determines the spontaneity of a process is the free energy. For a process to be spontaneous the free energy must be-ve. Reason (R ) : The change in free energy is related to the change in a process must always be positive if its is spontaneous.

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    Assertion (A): Internal energy change in a cyclic process is zero. Reason (R ) : Internal energy is a state funciton.

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