




To solve this question, we need to understand the formation of azo-dyes, which generally involves a diazonium salt and a coupling component. Here, sulfanilic acid undergoes a diazotization reaction followed by coupling with a nitrogen-rich compound to form an azo dye.
The correct option involves the reaction forming an azo group (-N=N-) linked between two aromatic rings. This is typically represented by \(Ar-N=N-Ar'\), where Ar and Ar' are aromatic groups.
Given the options, the correct azo-dye formed is represented in the following image:
Therefore, the correct answer is the final option illustrated above.
The reaction involves the diazotization of sulphanilic acid, which forms a diazonium salt. This diazonium salt then couples with the compound \( C_6H_5NH_2 \), leading to the formation of the azo-dye product \( Y \).
The structure of \( Y \) matches option (4) in which the diazonium ion is coupled with the benzene ring of \( C_6H_5NH_2 \), forming the characteristic azo linkage (\(-N=N-\)) between the two aromatic rings.
Thus, the correct answer is: Option (4)
A substance 'X' (1.5 g) dissolved in 150 g of a solvent 'Y' (molar mass = 300 g mol$^{-1}$) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent 'Y' is $____________ \(\times 10^{-2}\). (nearest integer)
[Given : $K_{b}$ of the solvent = 5.0 K kg mol$^{-1}$]
Assume the solution to be dilute and no association or dissociation of X takes place in solution.