Introducing a defect in a crystal by adding impurity is called …….. .

Answer

To answer the question, "Introducing a defect in a crystal by adding impurity is called ……..", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept of Crystal Defects**:
- In solid-state chemistry, crystals can have defects that affect their properties. These defects can be intrinsic (naturally occurring) or extrinsic (introduced by external means).

2. **Identifying the Role of Impurities**:
- Impurities are foreign atoms that are introduced into a crystal lattice. They can alter the electrical, optical, and mechanical properties of the material.

3. **Defining the Process of Introducing Impurities**:
- The process of adding impurities to a crystal to create defects is specifically termed "doping".

4. **Types of Doping**:
- Doping can be of two main types:
- **n-type doping**: where elements from group 15 (like phosphorus) are added, providing extra electrons.
- **p-type doping**: where elements from group 13 (like aluminum) are added, creating holes by accepting electrons.

5. **Conclusion**:
- Therefore, the correct term for introducing a defect in a crystal by adding impurity is **doping**.

### Final Answer:
Introducing a defect in a crystal by adding impurity is called **doping**.

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