(v) An essential constituent of analgam is :

Options

A. Hg
B. Ag
C. Au
D. Al

Explanation

To solve the question regarding the essential constituent of amalgam, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Amalgam**:
- Amalgam is a term used to describe a mixture or alloy of mercury with another metal. It is commonly used in dentistry and other applications.

2. **Identifying the Key Element**:
- The primary and essential constituent of any amalgam is mercury (Hg). This is because amalgams are specifically defined as alloys that include mercury.

3. **Examples of Amalgams**:
- Various metals can form amalgams with mercury. For instance:
- Sodium amalgam (Na + Hg)
- Zinc amalgam (Zn + Hg)
- In both cases, mercury is a crucial component.

4. **Conclusion**:
- Therefore, the essential constituent of amalgam is mercury.

### Final Answer:
The essential constituent of amalgam is **mercury**.

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