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A : C("diamond") rightarrow C("graphite"...

A : `C_("diamond") rightarrow C_("graphite")`
`Delta H and Delta U` are same for this reaction.
R: Entropy increases during the conversion of diamond to graphite.

A

If both Assertion & Reason are true and the reason is the correct explanation of the assertion , then mark (1)

B

If both Assertion & Reason are true and the reason is not the correct explanation of the assertion, then mark (2)

C

If Assertion is true statement but Reason is false, then mark (3)

D

If both Assertion is true statement but Reason is false, then mark (3)

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze the assertion (A) and the reason (R) provided. ### Step-by-Step Solution: 1. **Understanding the Assertion (A)**: - The assertion states that the change in enthalpy (ΔH) and the change in internal energy (ΔU) are the same for the reaction converting diamond to graphite. - In thermodynamics, ΔH and ΔU are related by the equation: \[ \Delta H = \Delta U + \Delta nRT \] where Δn is the change in the number of moles of gas, R is the gas constant, and T is the temperature in Kelvin. 2. **Analyzing the Reaction**: - The reaction involves the conversion of solid diamond (a more ordered structure) to solid graphite (a less ordered structure). - Since both reactants and products are solids, there is no change in the number of moles of gas (Δn = 0). Therefore, the equation simplifies to: \[ \Delta H = \Delta U \] - This means that for this specific reaction, ΔH and ΔU can be considered the same. 3. **Understanding the Reason (R)**: - The reason states that entropy increases during the conversion of diamond to graphite. - Entropy (S) is a measure of disorder or randomness in a system. Diamond has a more ordered structure compared to graphite, which has a layered structure allowing for more freedom of movement of atoms. - Therefore, when diamond is converted to graphite, the randomness increases, leading to an increase in entropy (ΔS > 0). 4. **Conclusion**: - The assertion (A) is **incorrect** because ΔH and ΔU are not the same in this case. - The reason (R) is **correct** because the entropy does indeed increase during the conversion from diamond to graphite. ### Final Answer: - Assertion (A) is false. - Reason (R) is true.
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