Step 1: Understanding the Concept:
A zwitterion is a dipolar ion formed by the internal transfer of a proton from an acidic group to a basic group within the same molecule.
Step 3: Detailed Explanation:
Sulfanilic acid (\(NH_2-C_6H_4-SO_3H\)) contains a basic amino group (\(-NH_2\)) and an acidic sulfonic acid group (\(-SO_3H\)).
The proton (\(H^+\)) from the \(-SO_3H\) group is transferred to the \(-NH_2\) group.
This results in a structure where the nitrogen carries a positive charge and the sulfonate group carries a negative charge.
Structure:
\[ \text{A benzene ring with } ^+NH_3 \text{ at one end and } SO_3^- \text{ at the para position.} \]
Step 4: Final Answer:
The zwitterion form of sulfanilic acid is \(^+NH_3-C_6H_4-SO_3^-\).
Step 1: Understanding the Concept:
Azo coupling is an electrophilic aromatic substitution reaction where a diazonium cation reacts with an activated aromatic ring (like phenol).
Step 3: Detailed Explanation:
Benzene diazonium chloride (\(C_6H_5N_2^+Cl^-\)) reacts with phenol in a cold, weakly alkaline medium (\(pH \approx 9-10\)).
The diazonium cation attacks the para position of the phenol ring.
The product is p-hydroxyazobenzene, which is an orange-coloured dye.
Reaction:
\[ C_6H_5-N \equiv N^+Cl^- + C_6H_5OH \xrightarrow{OH^-} C_6H_5-N=N-C_6H_4-OH + HCl \]
Step 4: Final Answer:
The reaction produces p-hydroxyazobenzene, an orange azo dye.