Question

Intensity or brightness of the colour depends on the presence of:

• A. Chromophore
• B. Auxochrome
• C. Mordants
• D. Pigments

Hint:

Chromophore = Color giver.
Auxochrome = Color intensifier/bonder.
Remember "Chromo" means color.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks to identify the specific part of a dye molecule that is responsible for its color and intensity.

Step 2: Detailed Explanation:

• A synthetic dye molecule generally consists of two main parts: a chromophore and an auxochrome.

• A Chromophore (A) is a chemical group (like -N=N-, -NO2) that contains unsaturated bonds capable of absorbing light in the visible spectrum. It is the "color-bearing" part of the molecule. The type and number of chromophores determine the wavelength absorbed and thus the intensity or brightness of the color.

• An Auxochrome (B) is a helper group (like -OH, -NH2) that does not produce color on its own but intensifies the color and, more importantly, allows the dye to "bond" with the fiber.

• Mordants (C) are chemicals (like alum) used to fix dyes to fabrics.

• Pigments (D) are insoluble colored particles used for surface coloring.

Step 3: Final Answer: Intensity/brightness primarily depends on the Chromophore.