What is true regarding the relative basic character of the following pairs ?

Options

A. `NH_3 gt NH_2OH`
B. `CH_3C^(-) gt NH_2^(-)`
C. ` C Cl_3 lt ^(-)CF_3`
D. neither is true

Explanation

To determine the relative basic character of the given pairs, we need to analyze the stability of the negative charge in each case. The stronger base will be the one where the negative charge is less stable, as it can more readily donate its lone pair of electrons to abstract a proton (H+).

### Step-by-Step Solution:

1. **Understanding Basicity**:
- A base is defined as a substance that can donate a pair of electrons or abstract a proton (H+). The strength of a base is determined by how readily it can donate its lone pair of electrons.

2. **Analyzing Pair A: Ammonia (NH3) vs. Hydroxylamine (NH2OH)**:
- Ammonia (NH3) has a lone pair of electrons on nitrogen that can be donated.
- Hydroxylamine (NH2OH) has an -OH group, which exerts a -I (inductive) effect, withdrawing electron density from the nitrogen.
- The presence of the -OH group makes the lone pair on nitrogen in hydroxylamine less available for donation compared to ammonia.
- **Conclusion**: Ammonia (NH3) is the stronger base compared to Hydroxylamine (NH2OH).

3. **Analyzing Pair B: Methyl anion (CH3-) vs. Amide ion (NH2-)**:
- The methyl anion (CH3-) has a negative charge on carbon, while the amide ion (NH2-) has a negative charge on nitrogen.
- Nitrogen is more electronegative than carbon, making the negative charge on nitrogen more stable than that on carbon.
- Therefore, the methyl anion, with the negative charge on carbon, is less stable and thus a stronger base.
- **Conclusion**: Methyl anion (CH3-) is the stronger base compared to Amide ion (NH2-).

4. **Analyzing Pair C: Methyl anion (CH3-) vs. Trifluoromethyl anion (CF3-)**:
- The methyl anion (CH3-) has a negative charge on carbon, while the trifluoromethyl anion (CF3-) has a negative charge on carbon but is stabilized by the three electronegative fluorine atoms.
- The presence of electronegative fluorines exerts a -I effect, stabilizing the negative charge on CF3-.
- Thus, the negative charge on CF3- is more stable than that on CH3-.
- **Conclusion**: Methyl anion (CH3-) is the stronger base compared to Trifluoromethyl anion (CF3-).

5. **Analyzing Pair D**:
- This pair was not explicitly mentioned in the transcript, but we can assume it follows similar reasoning.
- If one species has a negative charge on a more electronegative atom compared to another, it will generally be a weaker base.

### Final Conclusions:
- For Pair A: Ammonia (NH3) > Hydroxylamine (NH2OH)
- For Pair B: Methyl anion (CH3-) > Amide ion (NH2-)
- For Pair C: Methyl anion (CH3-) > Trifluoromethyl anion (CF3-)