Question

In the reaction A is

• A. HgSO₄/H₂SO₄
• B. Cu₂Cl₂
• C. H₃PO₂ and H₂O
• D. H⁺/H₂O

Answer 1

The Correct Option is C

The given reaction involves converting a diazonium salt into the corresponding benzene derivative. This is a common reaction where certain reagents are used to facilitate the reaction.

Let's analyze the options:

1. HgSO₄/H₂SO₄: This is typically used for oxymercuration-demercuration reactions, not for replacing diazonium groups.
2. Cu₂Cl₂: This reagent is used in Sandmeyer reactions, which are used to form aryl chlorides from diazonium salts but not for this transformation.
3. H₃PO₂ and H₂O: Hypophosphorous acid is used to reduce an aryl diazonium salt to the corresponding benzene. This matches the transformation observed in the chemical reaction given.
4. H⁺/H₂O: Although acidic conditions can sometimes aid in certain reactions, they aren't typically involved in transforming diazonium salts in this manner.

Based on the above analysis, the correct reagent for the reaction is:

H₃PO₂ and H₂O

This option is correct because hypophosphorous acid reduces the azo group effectively, leading to the deamination observed in the transformation of the given structure.

Conclusion: Option C, H₃PO₂ and H₂O, is the correct answer as it facilitates the reduction of the diazonium salt to benzene.