The correct statement(s) is /are :

Options

A. Boiling point of m-hydroxybenzaldehyde is greater than o-hydroxybenzaldehyde
B. Boiling point of `CHCl_(3)` is higher than `CCl_(4)`
C. Melting point `BeCl_(2)` is higher than `BeF_(2)`
D. Boiling point HF is greater than `CH_(3)F`

Explanation

To solve the question regarding the correct statements about the boiling and melting points of various compounds, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Boiling Point of Meta Hydroxybenzaldehyde vs. Ortho Hydroxybenzaldehyde**:
- **Meta Hydroxybenzaldehyde**: The structure does not allow for significant intramolecular hydrogen bonding.
- **Ortho Hydroxybenzaldehyde**: The ortho position allows for intramolecular hydrogen bonding, which stabilizes the molecule and increases the energy required to vaporize it.
- **Conclusion**: The boiling point of ortho hydroxybenzaldehyde is greater than that of meta hydroxybenzaldehyde.
- **Correct Statement**: **Incorrect** (the statement claims the opposite).

2. **Boiling Point of CHCl3 vs. Cl4**:
- **CHCl3 (Chloroform)**: This molecule is polar due to the presence of the carbon atom, which creates a dipole moment.
- **Cl4 (Tetrachlorine)**: This molecule is non-polar as the dipole moments of the chlorine atoms cancel each other out.
- **Conclusion**: The boiling point of CHCl3 is greater than that of Cl4 due to its polar nature.
- **Correct Statement**: **Correct**.

3. **Melting Point of BeCl2 vs. BeF2**:
- **BeCl2**: The chloride ion (Cl-) is larger than the fluoride ion (F-), leading to lower polarization and higher melting point.
- **BeF2**: The fluoride ion is smaller and more polarizable, leading to stronger interactions and a higher melting point.
- **Conclusion**: The melting point of BeCl2 is lower than that of BeF2.
- **Correct Statement**: **Incorrect** (the statement claims the opposite).

4. **Boiling Point of HF vs. CH3F**:
- **HF (Hydrogen Fluoride)**: Exhibits strong hydrogen bonding due to the presence of only one hydrogen atom bonded to fluorine.
- **CH3F (Fluoromethane)**: Although it is polar, the presence of three hydrogen atoms reduces the overall polarity compared to HF.
- **Conclusion**: The boiling point of HF is greater than that of CH3F due to stronger hydrogen bonding in HF.
- **Correct Statement**: **Correct**.

### Final Summary of Correct Statements:
- The correct statements are:
- Boiling point of CHCl3 is greater than Cl4.
- Boiling point of HF is greater than CH3F.