Which of the following do not match

Options

A. Plastic : amorphous solid
B. Graphite : Metallic solid
C. `P_4O_10` : Molecular solid
D. SiC-covalent solid

Answer

To solve the question of which of the following do not match, we will analyze each option given:

1. **Plastic - Amorphous Solid**
- **Analysis**: Plastic is indeed an amorphous solid. Amorphous solids lack a well-defined crystalline structure, and plastics typically exhibit this characteristic. Therefore, this pairing is correct.
- **Conclusion**: Matches.

2. **Graphite - Metallic Solid**
- **Analysis**: Graphite is not a metallic solid; it is an allotrope of carbon and is classified as a covalent solid. In graphite, carbon atoms are bonded by covalent bonds, forming layers that can slide over each other. Therefore, this pairing is incorrect.
- **Conclusion**: Does not match.

3. **P4O10 - Molecular Solid**
- **Analysis**: P4O10, known as tetraphosphorus decoxide, is indeed a molecular solid. It consists of discrete molecules held together by van der Waals forces. Thus, this pairing is correct.
- **Conclusion**: Matches.

4. **SiC - Covalent Solid**
- **Analysis**: Silicon carbide (SiC) is also a covalent solid. It consists of silicon and carbon atoms bonded together by strong covalent bonds, forming a rigid structure. Therefore, this pairing is correct.
- **Conclusion**: Matches.

### Final Answer:
The option that does not match is **Graphite - Metallic Solid**.