Arrange the following compounds in order of increaing basicity.
(a). `CH_(3)NH_(2),CH_(3)NH_(3)^(o+),CH_(3)NH^(-)`
(b) `CH_(3)O^(-),CH_(3)NH^(-),CH_(3)CH_(2)^(-)`.

Answer

To arrange the given compounds in order of increasing basicity, we will analyze each set of compounds based on their electron density and the presence of lone pairs.

### Part (a): Compounds - `CH3NH2`, `CH3NH3^+`, `CH3NH^-`

1. **Identify the compounds:**
- `CH3NH2` (Methylamine)
- `CH3NH3^+` (Methylammonium ion)
- `CH3NH^-` (Methylamide ion)

2. **Analyze basicity:**
- **`CH3NH2`**: This compound has a lone pair of electrons on the nitrogen atom, which can be donated, making it a weak base.
- **`CH3NH3^+`**: This is a positively charged ion with no lone pair available for donation, making it the least basic.
- **`CH3NH^-`**: This compound has a negative charge on nitrogen, which increases its electron density and makes it a stronger base than the others.

3. **Order of increasing basicity:**
- `CH3NH3^+` < `CH3NH2` < `CH3NH^-`

### Part (b): Compounds - `CH3O^-`, `CH3NH^-`, `CH3CH2^-`

1. **Identify the compounds:**
- `CH3O^-` (Methoxide ion)
- `CH3NH^-` (Methylamide ion)
- `CH3CH2^-` (Ethyl ion)

2. **Analyze basicity:**
- **`CH3O^-`**: The oxygen atom is more electronegative than nitrogen, which means it holds onto its electrons more tightly, making it less basic.
- **`CH3NH^-`**: The nitrogen atom has a negative charge and can donate electrons, making it a stronger base than methoxide.
- **`CH3CH2^-`**: The carbon atom with a negative charge is the least electronegative, allowing it to donate electrons more readily, making it the strongest base.

3. **Order of increasing basicity:**
- `CH3O^-` < `CH3NH^-` < `CH3CH2^-`

### Final Results:
- For part (a): `CH3NH3^+` < `CH3NH2` < `CH3NH^-`
- For part (b): `CH3O^-` < `CH3NH^-` < `CH3CH2^-`