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

Options

A. `NH_3 gt NH_2OH`
B. `CH_3^(-) 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 will analyze each pair step by step.

### Step 1: Analyze NH3 and NH2OH
- **NH3 (Ammonia)** has a nitrogen atom with a lone pair of electrons that can be donated to accept protons (H+), making it a good base.
- **NH2OH (Hydroxylamine)** also has a nitrogen atom with a lone pair, but it is attached to a hydroxyl (–OH) group. The –OH group exerts a –I (inductive) effect, which pulls electron density away from the nitrogen. This reduces the availability of the lone pair for donation.
- **Conclusion**: NH3 is more basic than NH2OH because the –OH group decreases the basicity of NH2OH.

### Step 2: Analyze CH3- and NH2-
- **CH3- (Methyl anion)** has a carbon atom with a negative charge. Carbon is less electronegative than nitrogen, which means it can donate its lone pair of electrons more readily.
- **NH2- (Amide anion)** also has a nitrogen atom with a negative charge, but nitrogen is more electronegative than carbon. This means that nitrogen holds onto its electrons more tightly than carbon does.
- **Conclusion**: CH3- is more basic than NH2- because carbon can donate its electrons more easily than nitrogen.

### Step 3: Analyze CCl3- and CF3-
- **CCl3- (Trichloromethyl anion)** has a carbon atom with a negative charge and is surrounded by three chlorine atoms. Chlorine has vacant 3d orbitals, which can help delocalize the negative charge, reducing the charge density on carbon.
- **CF3- (Trifluoromethyl anion)** also has a carbon atom with a negative charge, but fluorine is highly electronegative and pulls electron density away from the carbon, increasing the charge density on carbon.
- **Conclusion**: CCl3- is less basic than CF3- because the negative charge is more stabilized in CCl3- due to the presence of chlorine's vacant orbitals.

### Final Conclusion
- The order of basicity is:
- NH3 > NH2OH (A is correct)
- CH3- > NH2- (B is correct)
- CCl3- < CF3- (C is correct)

Thus, the correct answer for the question is A, B, C.

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