Arrange the following in decreasing order of their basic strength: ammonia, triethylamine, aniline, ethylamine and diethylamine.

Explanation

To arrange the given compounds (ammonia, triethylamine, aniline, ethylamine, and diethylamine) in decreasing order of their basic strength, we need to analyze the structure and electronic effects of each compound.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Ammonia (NH₃)
- Triethylamine (N(C₂H₅)₃)
- Aniline (C₆H₅NH₂)
...