The intermolecular forces of attraction (i.e., H-bonding and van der waal's forces) exist among polar and non-polar species which effect melting point, boiling point, solubility and viscosity of covalent compounds :
Q. Select the incorrect order of boiling point between the following compounds:

Options

A. `N_(2)HltCH_(3)N_(3)`
B. `Me_(2)SO_(4)ltH_(2)SO_(4)`
C. `Me_(3)BO_(3)ltB(OH)_(3)`
D. `BF_(3)ltBI_(2)`

Explanation

To determine the incorrect order of boiling points among the given compounds, we need to analyze the intermolecular forces present in each compound. The boiling point of a substance is influenced by the strength of these intermolecular forces, which include hydrogen bonding and van der Waals forces.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- The compounds mentioned are ammonia (NH3), methylhydrazine (CH3N3), dimethyl sulfate (Me2SO4), sulfuric acid (H2SO4), trimethyl borate (Me3BO3), boric acid (H3BO3), boron trifluoride (BF3), and bismuth triiodide (BiI3).

2. **Analyze Intermolecular Forces**:
- **Ammonia (NH3)**: Exhibits strong hydrogen bonding due to the presence of nitrogen, which is highly electronegative.
- **Methylhydrazine (CH3N3)**: Also has hydrogen bonding but is less effective compared to ammonia due to steric hindrance.
- **Dimethyl Sulfate (Me2SO4)**: Lacks hydrogen bonding; it primarily exhibits van der Waals forces.
- **Sulfuric Acid (H2SO4)**: Exhibits hydrogen bonding, leading to a higher boiling point.
- **Trimethyl Borate (Me3BO3)**: Lacks hydrogen bonding; it primarily exhibits van der Waals forces.
- **Boric Acid (H3BO3)**: Exhibits hydrogen bonding, leading to a higher boiling point.
- **Boron Trifluoride (BF3)**: Lacks hydrogen bonding; it primarily exhibits van der Waals forces.
- **Bismuth Triiodide (BiI3)**: Has a larger molecular mass, leading to stronger van der Waals forces.

3. **Compare Boiling Points**:
- **NH3** > **CH3N3** (due to stronger hydrogen bonding in NH3)
- **H2SO4** > **Me2SO4** (due to hydrogen bonding in H2SO4)
- **H3BO3** > **Me3BO3** (due to hydrogen bonding in H3BO3)
- **BiI3** > **BF3** (due to higher molecular mass of BiI3)

4. **Identify the Incorrect Order**:
- The incorrect order of boiling points is likely to be between compounds that do not exhibit hydrogen bonding and have similar molecular masses. For instance, comparing **Me2SO4** and **H2SO4**, the order should be **H2SO4** > **Me2SO4** due to hydrogen bonding in H2SO4.

5. **Conclusion**:
- The incorrect order of boiling points among the mentioned compounds is the one that suggests that methylhydrazine (CH3N3) has a higher boiling point than ammonia (NH3), which is incorrect due to the stronger hydrogen bonding in ammonia.