Most commonly used tranquillizers are derivatives of

Options

A. Acetic acid
B. Salicylic acid
C. Barbituric acid
D. Sulphanilamide

Answer

### Step-by-Step Solution

1. **Understanding Tranquilizers**: Tranquilizers are medications that primarily act on the central nervous system (CNS). They are used to treat conditions such as anxiety, depression, and stress by promoting relaxation and calmness.

2. **Mechanism of Action**: These medications work by slowing down the activity of the brain, which can induce sleep and alleviate symptoms associated with mental instability.

3. **Derivatives of Barbituric Acid**: The most commonly used tranquilizers are derivatives of barbituric acid. These derivatives are known as barbiturates.

4. **Classification of Barbiturates**: Barbiturates can be classified as hypnotics (sleep-inducing), anesthetics, or anti-depressants. They are effective in treating various mental health issues due to their calming effects.

5. **Examples of Barbiturates**: Some common examples of barbiturates include:
- Veronal
- Seconal
- Luminal

6. **Chemical Structure**: The structure of barbituric acid consists of a six-membered ring with nitrogen (N) and oxygen (O) atoms. The derivatives of this structure lead to the formation of various tranquilizers.

7. **Conclusion**: Therefore, the answer to the question regarding the most commonly used tranquilizers is that they are derivatives of barbituric acid.

### Final Answer
The most commonly used tranquilizers are derivatives of **barbituric acid**.

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