Aniline is reacted with bromine water and the resulting product is treated with an aqueous solution of sodium nitrite in presence of dilute hydrochloric acid. The compound so formed is converted into a tetrafluoroborate which is subsequently heated. The final product is

Question

Which of the following reactions will not give a primary amine?

Answer 1

The given problem involves a multi-step chemical reaction sequence starting from aniline. Let's break down the steps to determine the final product.

The first step is the reaction of aniline with bromine water. Aniline is known to react with bromine water in the presence of water to form a tribromo derivative due to the activation of the benzene ring by the amino group. The product formed is 2,4,6-tribromoaniline.
In the second step, the 2,4,6-tribromoaniline is treated with an aqueous solution of sodium nitrite in the presence of dilute hydrochloric acid. This is a diazotization reaction where the amino group (-NH₂) is converted into a diazonium salt. The formed product is 2,4,6-tribromo-benzenediazonium chloride.
Following that, the diazonium salt is converted into its tetrafluoroborate form by reacting it with tetrafluoroboric acid (HBF₄). Thus, 2,4,6-tribromo-benzenediazonium tetrafluoroborate is obtained.
Finally, heating the tetrafluoroborate salt leads to the decomposition of the diazonium salt, releasing nitrogen gas and forming 2,4,6-tribromofluorobenzene through a nucleophilic substitution reaction with fluoroborate ion as the nucleophile.

The final product is 2,4,6-tribromofluorobenzene. This corresponds to the correct option provided in the question.

Reasons why other options are incorrect:

1,3,5-Tribromobenzene: This would require a different set of reactions, not involving diazotization and fluorination.
p-Bromofluorobenzene: This product is not achievable from tribromination of aniline and subsequent reactions.
p-Bromoaniline: This compound is not feasible through the given reaction pathway as multiple bromination at specific ortho and para positions occurs due to the activating nature of the -NH₂ group.

Thus, the correct answer is 2,4,6-tribromofluorobenzene.

Answer 2

The given problem involves a multi-step chemical reaction sequence starting from aniline. Let's break down the steps to determine the final product.

The first step is the reaction of aniline with bromine water. Aniline is known to react with bromine water in the presence of water to form a tribromo derivative due to the activation of the benzene ring by the amino group. The product formed is 2,4,6-tribromoaniline.
In the second step, the 2,4,6-tribromoaniline is treated with an aqueous solution of sodium nitrite in the presence of dilute hydrochloric acid. This is a diazotization reaction where the amino group (-NH₂) is converted into a diazonium salt. The formed product is 2,4,6-tribromo-benzenediazonium chloride.
Following that, the diazonium salt is converted into its tetrafluoroborate form by reacting it with tetrafluoroboric acid (HBF₄). Thus, 2,4,6-tribromo-benzenediazonium tetrafluoroborate is obtained.
Finally, heating the tetrafluoroborate salt leads to the decomposition of the diazonium salt, releasing nitrogen gas and forming 2,4,6-tribromofluorobenzene through a nucleophilic substitution reaction with fluoroborate ion as the nucleophile.

The final product is 2,4,6-tribromofluorobenzene. This corresponds to the correct option provided in the question.

Reasons why other options are incorrect:

1,3,5-Tribromobenzene: This would require a different set of reactions, not involving diazotization and fluorination.
p-Bromofluorobenzene: This product is not achievable from tribromination of aniline and subsequent reactions.
p-Bromoaniline: This compound is not feasible through the given reaction pathway as multiple bromination at specific ortho and para positions occurs due to the activating nature of the -NH₂ group.

Thus, the correct answer is 2,4,6-tribromofluorobenzene.

The Correct Option is D