From the following pair, select the stronger base:
p-methoxy aniline or p-cyanoaniline

Answer

To determine which compound is the stronger base between p-methoxy aniline and p-cyanoaniline, we need to analyze the effects of the substituents on the aniline nitrogen atom.

### Step-by-Step Solution:

**Step 1: Understand the Structures**
- p-Methoxy aniline has a methoxy group (-OCH3) attached to the para position of the aniline ring.
- p-Cyanoaniline has a cyano group (-CN) attached to the para position of the aniline ring.

**Step 2: Identify the Nature of Substituents**
- The methoxy group is an electron-donating group (EDG) through resonance (it has a +M effect), which increases the electron density on the nitrogen atom of the aniline.
- The cyano group is an electron-withdrawing group (EWG) through resonance (it has a -M effect), which decreases the electron density on the nitrogen atom of the aniline.

**Step 3: Analyze the Effect on Basicity**
- A stronger base is characterized by a higher electron density on the nitrogen atom, which allows it to donate its lone pair more readily.
- In p-methoxy aniline, the electron-donating effect of the methoxy group increases the electron density on the nitrogen, making it a stronger base.
- In p-cyanoaniline, the electron-withdrawing effect of the cyano group decreases the electron density on the nitrogen, making it a weaker base.

**Step 4: Conclusion**
- Since p-methoxy aniline has an increased electron density on the nitrogen due to the electron-donating effect of the methoxy group, it is the stronger base compared to p-cyanoaniline.

### Final Answer:
**p-Methoxy aniline is the stronger base compared to p-cyanoaniline.**

---