JEE Chemistry 2023 Question with Solution

Step-by-step solution

Standard Method

Given: A diazonium salt reacts with 1-naphthyl amine.

Find: The correct colour of the product.

This is an example of a diazo coupling reaction, where a diazonium salt reacts with 1-naphthylamine to form an azo dye. The product is red in colour due to the extensive conjugation in the azo compound.

Therefore, the correct option is C.

Reaction Identification

The correct answer is (C) : Red.

Common mistakes

• Confusing the reaction with a simple substitution reaction is incorrect because this is specifically a diazo coupling reaction. Identify the azo dye formation first before deciding the product colour.

• Assuming the product is colourless or white is incorrect because extensive conjugation in azo compounds usually gives strongly coloured products. Check for the presence of the $-N=N-$ linkage.