The groups which are responsible for imparting colour to dyes is/are

Options

A. `-NO_(2)`
B. `-NO`
C. `-N -=N`
D. All of these

Answer

To solve the question regarding the groups responsible for imparting color to dyes, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Dyes and Color**: Dyes are substances that impart color to materials. The color observed in dyes is due to specific groups within their molecular structure.

2. **Identifying Chromophores**: The groups responsible for the color in dyes are known as chromophores. Chromophores are parts of the molecule that can absorb visible light and, as a result, produce color.

3. **Absorption of Light**: When light hits a dye, certain wavelengths are absorbed by the chromophores. The wavelengths that are not absorbed are reflected or transmitted, and this is what we perceive as the color of the dye.

4. **Examples of Chromophores**: Common examples of chromophores include groups like -N=N- (azo group), -C=O (carbonyl group), -C=C- (double bond), and others that can absorb light in the visible spectrum.

5. **Conclusion**: Therefore, the groups responsible for imparting color to dyes are indeed chromophores. If the question provides options, all of them would typically be examples of chromophores.

### Final Answer:
The groups responsible for imparting color to dyes are called chromophores.

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