Assertion: Lithium fluoride is most covalent in nature.
Reason: Small anion can be easily distorted.

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.

Explanation

To analyze the assertion and reason provided in the question, we will break down the concepts involved step by step.

### Step 1: Understand the Assertion
The assertion states that "Lithium fluoride is most covalent in nature." Covalent character in ionic compounds is influenced by the size of the ions involved. Generally, smaller ions have a higher charge density, which can lead to distortion of the electron cloud of the anion, contributing to covalent character.

**Hint:** Consider the size and charge of lithium and fluoride ions when evaluating covalent character.

### Step 2: Analyze the Reason
The reason given is that "Small anion can be easily distorted." This statement is true in the context of covalent character. A smaller anion, such as fluoride (F⁻), can be distorted by a cation with a high charge density, like lithium (Li⁺). However, the assertion claims that lithium fluoride is the most covalent, which requires further examination.

**Hint:** Think about how the size of the cation and anion affects their ability to distort each other.

### Step 3: Compare with Other Halides
When comparing lithium fluoride to other halides, it is important to note that while lithium is a small cation, fluoride is also a small anion. However, when considering other halides like lithium iodide (LiI), the iodide ion (I⁻) is larger and can be distorted more easily by the lithium ion, leading to greater covalent character in LiI compared to LiF.

**Hint:** Look at the trend in ionic sizes and how they affect covalent character in different halides.

### Step 4: Conclusion
Both the assertion and the reason are incorrect. Lithium fluoride is not the most covalent halide; rather, lithium iodide exhibits more covalent character due to the larger size of the iodide ion, which can be distorted more easily. Therefore, the correct answer is that both the assertion and reason are false.

**Final Answer:** Both assertion and reason are incorrect.