Choose the correct statement(s) regarding lithium and alkali metals.
I. Lithium is much harder. Its m.p. and b.p. are higher than other alkali metals.
II. Lithium is highly reactive and strongest reducing agent.
III Lithium is deliquescent and crystallises as hydrates.

Options

A. I and III
B. II and III
C. Only I
D. All are correct

Answer

To solve the question regarding the statements about lithium and alkali metals, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyzing Statement I:**
- Statement: "Lithium is much harder. Its m.p. and b.p. are higher than other alkali metals."
- Explanation: This statement is correct. Lithium is indeed harder than other alkali metals and has higher melting and boiling points compared to sodium, potassium, and other alkali metals. This is due to its smaller atomic size and stronger metallic bonding, which results in its anomalous behavior compared to the other alkali metals.

2. **Analyzing Statement II:**
- Statement: "Lithium is highly reactive and strongest reducing agent."
- Explanation: This statement is partially correct. While lithium is a strong reducing agent, it is not highly reactive compared to other alkali metals. In fact, lithium is the least reactive of all the alkali metals. Therefore, this statement is incorrect as it misrepresents the reactivity of lithium.

3. **Analyzing Statement III:**
- Statement: "Lithium is deliquescent and crystallizes as hydrates."
- Explanation: This statement is correct. Lithium compounds, such as lithium chloride (LiCl), are deliquescent and can crystallize with water molecules, forming hydrates. For example, lithium chloride can exist as LiCl·2H2O. Thus, this statement is true.

### Conclusion:
Based on the analysis:
- Statement I is correct.
- Statement II is incorrect.
- Statement III is correct.

Thus, the correct statements regarding lithium and alkali metals are **I and III**.

### Final Answer:
The correct statements are I and III.

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