Assertion : The presence of reactants in a closed vessel made of conducting material is an example of a closed system.
Reason : In a closed system, there is no exchange of matter but exchange of energy is possible between the system and the surroundings.

Options

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.

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "the presence of reactants in a closed vessel made of conducting material is an example of a closed system."

- A closed system is defined as one where there is no exchange of matter with the surroundings, but energy can be exchanged.
- The mention of a "closed vessel made of conducting material" indicates that while the vessel does not allow matter to escape, it can conduct heat (energy) to its surroundings.

**Conclusion for Step 1:** The assertion is true because a closed vessel made of conducting material indeed represents a closed system.

### Step 2: Understand the Reason
The reason states that "in a closed system, there is no exchange of matter but exchange of energy is possible between the system and the surroundings."

- This statement is a fundamental definition of a closed system in thermodynamics.
- It accurately describes the characteristics of a closed system, where matter remains contained, but energy can be transferred in the form of heat or work.

**Conclusion for Step 2:** The reason is also true as it correctly describes the nature of a closed system.

### Step 3: Analyze the Relationship
Now, we need to determine if the reason provided correctly explains the assertion.

- Since the assertion is about a closed system and the reason defines what a closed system is, the reason does indeed explain the assertion well.

### Final Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Therefore, the correct answer is:

**Both assertion and reason are true, and the reason is the correct explanation of the assertion.**

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