Verified Solution • 2025–26 Session moderate

QJEEAdv08Ch4b0f: JEE Advanced 2008 Chemistry - Class 12 JEEAdv08Ch4b0f Solution: Statement 1 : Aniline on reaction with NaNO /HCl at 0 C…

Statement 1 : Aniline on reaction with NaNO 2_2 /HCl at 0 ∘^\circ C followed by coupling with β\beta -naphthol gives a dark blue coloured precipitate.

Statement 2 : The colour of the compound formed in the reaction of aniline with NaNO 2_2 /HCl at 0 ∘^\circ C followed by coupling with β\beta -naphthol is due to the extended conjugation.

Multiple Choice Options

  • A Statement 1 is True, Statement 2 is True; Statement 2 is a CORRECT explanation for Statement 1.
  • B Statement 1 is True, Statement 2 is True; Statement 2 is a NOT CORRECT explanation for Statement 1.
  • C Statement 1 is True, Statement 2 is False.
  • D Statement 1 is False, Statement 2 is True.

Step-by-Step Verified Solution

Let us discuss the given statements one by one.

Statement 1 : Aniline reacts with NaNO 2_2 /HCl at 273 K to form colourless diazonium salt.

IIT-JEE 2008 Paper 2 Offline Chemistry - Compounds Containing Nitrogen Question 8 English Explanation 1

Benzene diazonium chloride is then coupled with β\beta -naphthol to yield a dark red or orange coloured dye as shown in the reaction below:

IIT-JEE 2008 Paper 2 Offline Chemistry - Compounds Containing Nitrogen Question 8 English Explanation 2

Thus, the statement 1 is false as the colour of the precipitate formed is orange red not blue. As we have already seen in the above mentioned reactions that the colour compound (dye) formed in the reaction of aniline with NaNO 2_2 /HCl at 0 ∘^\circ C was due to the successive coupling of diazonium salt with β\beta -naphthol. Hence, statement 2 is true.

As a result, Statement 1 is False and Statement 2 is true.

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