Greater is the stability of the substituted ammonium cation, stronger should be the corresponding amine as a base. Thus, the order of basicity of aliphatic amines should be: primary > secondary > tertiary, which is opposite to the inductive effect based order. Secondly, when the alkyl group is small, like-`CH_3` group, there is no steric hindrance to H-bonding. In case the alkyl group is bigger than `CH_3` group, there will be steric hinderance to H-bonding. Therefore, the change of nature of the alkyl group, e.g.,from-`CH_3` to-`C_2 H_5 `results in change of the order of basic strength. In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion (A): Greater is the stability of the substituted ammonium cation, stronger is the corresponding amine as a base. Reason (R): The order of basicity of aliphatic amines is: primary > secondary > tertiary.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement
D. Assertion is wrong statement but reason is correct statement

Explanation

To solve the question, we need to analyze the assertion and reason provided in the context of the basicity of aliphatic amines.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Greater is the stability of the substituted ammonium cation, stronger is the corresponding amine as a base."
- This is true because a more stable ammonium cation indicates that the amine can better donate its lone pair of electrons, thus acting as a stronger base.

2. **Understanding the Reason (R)**:
- The reason states that "The order of basicity of aliphatic amines is: primary > secondary > tertiary."
- This statement is not entirely accurate. While primary amines are generally stronger bases than tertiary amines due to steric hindrance, the order of basicity is influenced by both inductive effects and steric factors. Tertiary amines can have higher electron density due to the presence of three alkyl groups, but they also experience steric hindrance that limits their ability to interact with protons.

3. **Analyzing the Relationship**:
- The assertion is correct, as it reflects the relationship between stability and basicity.
- The reason, however, is misleading because it does not consider the full context of steric hindrance and the inductive effects that influence the basicity of amines.

4. **Conclusion**:
- Since the assertion is correct and the reason is incorrect, the correct answer is that the assertion is true, but the reason is false.

### Final Answer:
- The assertion is correct, but the reason is incorrect.