Assertion: Anilinium chloride is more acidic than ammonium chloride.

Reason: Anilinium ion is resonance stabilized.

Assertion is correct but the Reason is incorrect.

The correct answer is option 3. Assertion is correct but the Reason is incorrect.

Let us break down the assertion and reason to determine their validity and the relationship between them.

Assertion: Anilinium chloride is more acidic than ammonium chloride.

To understand this, we should compare the acidity of the conjugate acids of aniline and ammonia:

Anilinium ion (\( \text{C}_6\text{H}_5\text{NH}_3^+ \)): This ion is formed when aniline (\( \text{C}_6\text{H}_5\text{NH}_2 \)) accepts a proton.

Ammonium ion (\( \text{NH}_4^+ \)): This ion is formed when ammonia (\( \text{NH}_3 \)) accepts a proton.

Anilinium ion is generally more acidic than the ammonium ion. This is because the aniline conjugate base (\( \text{C}_6\text{H}_5\text{NH}_2 \)) is less basic than ammonia (\( \text{NH}_3 \)), making the anilinium ion more willing to donate a proton compared to the ammonium ion. This makes anilinium chloride more acidic than ammonium chloride.

Reason: Anilinium ion is resonance stabilized.

The anilinium ion (\( \text{C}_6\text{H}_5\text{NH}_3^+ \)) does not exhibit resonance stabilization because the positive charge on the nitrogen atom cannot delocalize into the benzene ring. However, aniline (\( \text{C}_6\text{H}_5\text{NH}_2 \)) is stabilized by resonance when it loses a proton, forming a conjugate base that is resonance stabilized.

Analysis of Assertion and Reason:

The assertion is correct: Anilinium chloride is indeed more acidic than ammonium chloride. The reason provided is incorrect: The anilinium ion itself is not resonance stabilized. Instead, the aniline molecule (the conjugate base of the anilinium ion) is resonance stabilized, which explains why aniline is a weaker base than ammonia, making anilinium ion more acidic than ammonium ion.

Conclusion: The correct option is: Assertion is correct but the Reason is incorrect.