Which of the following element do not form carbide ?

Options

A. (a) B
B. (b) Al
C. (c) In
D. (d) Ga

Answer

To determine which elements do not form carbides among the members of the boron family (Group 13), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Carbides**:
- Carbides are compounds formed when an element reacts with carbon. The ability of an element to form a carbide depends on its size and the nature of the bond it can form with carbon.

2. **Identify the Members of the Boron Family**:
- The boron family consists of the following elements: Boron (B), Aluminium (Al), Gallium (Ga), Indium (In), and Thallium (Tl).

3. **Analyze the Size of Carbon**:
- Carbon is a small element with a small atomic radius. This allows it to form stable bonds with other small elements.

4. **Compare the Sizes of Boron and Aluminium with Carbon**:
- Boron and Aluminium have atomic sizes that are comparable to carbon. Therefore, they can form stable carbides with carbon.

5. **Evaluate the Sizes of Gallium and Indium**:
- Gallium and Indium have larger atomic sizes compared to carbon. As a result, they are less likely to form stable carbides. When they do form carbides, these are generally unstable.

6. **Conclusion**:
- Based on the analysis, Boron and Aluminium can form carbides, while Indium and Gallium do not form stable carbides. Therefore, the elements that do not form carbides are Indium (In) and Gallium (Ga).

### Final Answer:
Indium (In) and Gallium (Ga) do not form stable carbides.

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