Which of the following compounds can form H-bonding with each other ?

Options

A. `CH_(3)CO OH and H_(2)O`
B. Phenol and `CH_(4)`
C. `CHF_(3)` and acetone
D. `PH_(3)` and HF

Explanation

To determine which compounds can form hydrogen bonding with each other, we need to follow these steps:

### Step 1: Understand Hydrogen Bonding
Hydrogen bonding occurs when hydrogen is covalently bonded to highly electronegative atoms such as nitrogen (N), oxygen (O), or fluorine (F). These electronegative atoms must also have lone pairs of electrons to accept the hydrogen bond.

**Hint:** Look for hydrogen atoms bonded to N, O, or F in the compounds.

### Step 2: Analyze Each Compound
Let’s analyze the given compounds one by one:

1. **Acetic Acid (CH3COOH) and Water (H2O)**:
- Acetic acid has an -OH group where hydrogen is bonded to oxygen.
- Water also has hydrogen atoms bonded to oxygen.
- Both have the necessary electronegative atom (O) and can form hydrogen bonds with each other.

**Hint:** Check for -OH groups in the compounds.

2. **Phenol (C6H5OH) and Methane (CH4)**:
- Phenol has an -OH group, allowing it to form hydrogen bonds.
- Methane has hydrogen atoms bonded to carbon, which is not electronegative enough to form hydrogen bonds.
- Therefore, phenol can form hydrogen bonds, but methane cannot.

**Hint:** Identify the presence of -OH in one compound and the absence of electronegative bonding in another.

3. **Acetone (CH3COCH3) and Trifluoromethane (CHF3)**:
- Acetone has a carbonyl group (C=O) but does not have hydrogen bonded to O, N, or F.
- In CHF3, the hydrogen is bonded to carbon, which is not electronegative enough.
- Thus, neither can form hydrogen bonds with each other.

**Hint:** Look for the presence of a carbonyl group without an attached hydrogen to O, N, or F.

4. **Phosphine (PH3)**:
- Phosphine has hydrogen atoms bonded to phosphorus, which is not as electronegative as N, O, or F.
- It cannot participate in hydrogen bonding due to the lack of a suitable electronegative atom.

**Hint:** Remember that hydrogen must be bonded to highly electronegative atoms to form hydrogen bonds.

### Step 3: Conclusion
From the analysis:
- **Only Acetic Acid (CH3COOH) and Water (H2O)** can form hydrogen bonds with each other.
- Other combinations either lack the necessary electronegative atoms or have hydrogen bonded to less electronegative atoms.

**Final Answer:** Acetic Acid (CH3COOH) and Water (H2O) can form hydrogen bonding with each other.