Assertion : Anilinium chloride is more acidic than ammonium chloride.
Reason : Anilinium chloride is resonance stabilised

Options

A. a. if both assertion and reason are true and reason is thr correct explanation of assertion
B. b. If both assertion and reason are true but reason is not the correct explanation of assertion
C. c. If assertion is true but reason is false
D. d. If both assertion and reason are false.

Explanation

To solve the question, we need to analyze the assertion and reason provided regarding the acidity of anilinium chloride and ammonium chloride.

### Step-by-Step Solution:

1. **Understanding the Compounds**:
- **Anilinium Chloride**: This is the salt formed from aniline (C6H5NH2) and hydrochloric acid (HCl). Its structure can be represented as C6H5NH3^+ Cl^−.
- **Ammonium Chloride**: This is the salt formed from ammonia (NH3) and hydrochloric acid (HCl). Its structure is NH4^+ Cl^−.

2. **Acidity Concept**:
- Acidity is defined as the ability of a compound to donate a proton (H^+). The more stable the conjugate base after the proton is removed, the stronger the acid.
- The stability of the conjugate base is often related to the delocalization of charge. Delocalized charges are more stable than localized charges.

3. **Analyzing Anilinium Chloride**:
- When anilinium chloride donates a proton (H^+), it forms aniline (C6H5NH2).
- The conjugate base (aniline) has a lone pair of electrons on the nitrogen that can participate in resonance with the benzene ring. This delocalization stabilizes the aniline molecule.

4. **Analyzing Ammonium Chloride**:
- When ammonium chloride donates a proton, it forms ammonia (NH3).
- The conjugate base (NH3) does not have any resonance stabilization. The lone pair on nitrogen is localized and does not participate in any delocalization.

5. **Comparing Acidity**:
- Since the conjugate base of anilinium chloride (aniline) is resonance-stabilized, it is more stable compared to the conjugate base of ammonium chloride (NH3), which is not resonance-stabilized.
- Therefore, anilinium chloride is more acidic than ammonium chloride.

6. **Conclusion on Assertion and Reason**:
- The assertion that "Anilinium chloride is more acidic than ammonium chloride" is **true**.
- The reason that "Anilinium chloride is resonance stabilized" is also **true**, as the lone pair in aniline can delocalize.
- However, the reason does not fully explain the assertion because it does not address the comparison with ammonium chloride directly.

### Final Answer:
The assertion is true, but the reason is not the correct explanation of the assertion. Therefore, the correct option is **C**: Assertion is true but the reason is false.