(A): Noble gases are sparingly soluble in water
(R): Neon has high positive electron gain enthalpy. 

Options

A. a. Both A & R are true, R is the correct explanation of A
B. b. Both A & R are true, R is not correct explanation of A
C. c. A is true, R is false
D. d. A is false, R is true

Answer

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 that "Noble gases are sparingly soluble in water."

- Noble gases, which include helium, neon, argon, krypton, and xenon, are known for their lack of reactivity due to their complete valence electron shells.
- This complete electron configuration leads to very weak interactions with water molecules, resulting in their sparing solubility.
- Therefore, the assertion is **true**.

### Step 2: Analyze the Reason (R)
The reason states that "Neon has high positive electron gain enthalpy."

- Electron gain enthalpy refers to the energy change when an electron is added to a neutral atom in the gas phase.
- For noble gases, this value is generally positive, indicating that energy is required to add an electron, which is consistent with their stable electron configuration.
- Neon, being a noble gas, does have a positive electron gain enthalpy, but it is important to note that this does not directly explain why noble gases are sparingly soluble in water.
- Therefore, the reason is also **true**, but it does not provide a correct explanation for the assertion.

### Step 3: Conclusion
Since both the assertion and reason are true, but the reason does not explain the assertion, the correct answer is that both A and R are true, but R is not the correct explanation of A.

### Final Answer
Both A and R are true; R is not the correct explanation of A.

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