Which of the following set is having correct statements here regarding both B and Al?
1. They react with HCl to form chlorides
3. They burn in oxygen to give oxides at high temperature
4. Their halides are Lewis acids

Options

A. 1, 4
B. 3, 4
C. 2, 3, 4
D. 1, 2, 3, 4

Answer

To solve the question regarding the correct statements about boron (B) and aluminum (Al), we will analyze each statement provided:

1. **Statement 1: They react with HCl to form chlorides.**
- Boron does not react with hydrochloric acid (HCl) to form chlorides, while aluminum does react with HCl to form aluminum chloride (AlCl3) and hydrogen gas (H2). Therefore, this statement is **incorrect** for boron.

2. **Statement 2: They burn in oxygen to give oxides at high temperature.**
- Boron reacts with oxygen at high temperatures to form boron trioxide (B2O3). Aluminum also reacts with oxygen to form aluminum oxide (Al2O3). Thus, this statement is **correct** for both elements.

3. **Statement 3: Their halides are Lewis acids.**
- Both aluminum halides (AlX3) and boron halides (BX3) are known to be Lewis acids because they are electron deficient (they have incomplete octets). Therefore, this statement is **correct** for both boron and aluminum.

4. **Statement 4: They combine with nitrogen to form nitrides.**
- Boron reacts with nitrogen to form boron nitride (BN), and aluminum reacts with nitrogen to form aluminum nitride (AlN). Thus, this statement is **correct** for both elements.

Now, summarizing the correctness of the statements:
- Statement 1: Incorrect (only Al reacts with HCl)
- Statement 2: Correct
- Statement 3: Correct
- Statement 4: Correct

Thus, the correct set of statements regarding both boron and aluminum is **2, 3, and 4**.

### Final Answer:
The correct option is **C (2, 3, and 4)**.