A : Among all ortho halophenol , fluorophenol is least acidic .
R : Ortho - fluorophenol forms intramolecular H - bond .

Options

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 but 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 and Reason are false statements , then mark (4)

Answer

To analyze the assertion (A) and reason (R) provided in the question, we will break down the concepts step by step.

### Step 1: Understanding the Assertion (A)
The assertion states that "Among all ortho halophenols, fluorophenol is least acidic."

- **Explanation**: In ortho halophenols, the presence of halogen atoms (like fluorine, chlorine, bromine, and iodine) can influence the acidity of the phenolic compound. Acidity in phenols is generally affected by the ability of the compound to donate a proton (H⁺).

### Step 2: Understanding the Reason (R)
The reason states that "Ortho-fluorophenol forms intramolecular H-bond."

- **Explanation**: Intramolecular hydrogen bonding occurs when a hydrogen bond forms within the same molecule. In the case of ortho-fluorophenol, the fluorine atom can form a strong hydrogen bond with the hydrogen atom of the hydroxyl group (-OH). This intramolecular hydrogen bonding stabilizes the structure and makes it less likely for the compound to lose the H⁺ ion, thereby reducing its acidity.

### Step 3: Analyzing the Relationship Between A and R
Now, we need to determine if the reason (R) correctly explains the assertion (A).

- **Analysis**: The assertion is true because ortho-fluorophenol is indeed less acidic compared to other ortho halophenols. The reason is also true because the formation of intramolecular hydrogen bonding in ortho-fluorophenol does hinder the release of H⁺ ions, thus contributing to its lower acidity. Therefore, the reason provides a correct explanation for the assertion.

### Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion.

### Final Answer
- Assertion (A) is true: Among all ortho halophenols, fluorophenol is least acidic.
- Reason (R) is true: Ortho-fluorophenol forms intramolecular H-bond.
- The reason is the correct explanation of the assertion.

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