Hydrogen bond is the given to the relatively weak secondry interaction between a hydrogen atom bound to an electronegative atom and another atom which is also generally electronegative and which has one or more lone pairs and can thus acts as a base. We can give the follwoing generalized representation of hydrogen bond.
`overset(delta-)(X)-overset(delta+)(H)...Y`
Bond dissociation energy of H-bond ranges from 8 and 42kJ/ol, and the most commonly encountred hydrogen bonds are `O-H...O, N-H...O and F-H..E`.
Q.Which of the following interaction has energy between 8-42kJ/mol?

Options

A. `Na^(+):C Cl_(4)`
B. `CHCl_(3):Br^(-)`
C. `C_(6)H_(6):C Cl_(4)`
D. `H_(2)O: HCN`

Explanation

To solve the question regarding which interaction has a bond dissociation energy between 8-42 kJ/mol, we will analyze the given interactions step by step.

### Step 1: Understand the Nature of Hydrogen Bonds
Hydrogen bonds are relatively weak secondary interactions that occur between a hydrogen atom covalently bonded to an electronegative atom (like O, N, or F) and another electronegative atom that has lone pairs. The bond dissociation energy of hydrogen bonds typically ranges from 8 to 42 kJ/mol.

**Hint:** Remember that hydrogen bonds are formed with electronegative atoms and involve lone pairs.

### Step 2: Analyze Each Interaction
We need to evaluate the interactions provided in the question to identify which one involves a hydrogen bond.

1. **Na⁺ + CCl₄**: This interaction involves an ion-dipole interaction, which is not a hydrogen bond. The bond energy is less than 8 kJ/mol.

**Hint:** Look for the presence of hydrogen atoms bonded to electronegative atoms in the interactions.

2. **CHCl₃ + Br⁻**: This interaction also involves an ion-dipole interaction, which is weaker and does not involve hydrogen bonding. The energy is again less than 8 kJ/mol.

**Hint:** Ion-dipole interactions typically do not fall within the hydrogen bond energy range.

3. **C₂H₆ + CCl₄**: This interaction is characterized by London dispersion forces, which are very weak and have energies less than 8 kJ/mol.

**Hint:** London dispersion forces are not hydrogen bonds and have very low bond dissociation energies.

4. **H₂O · HCN**: This interaction is a classic example of a hydrogen bond. The hydrogen atom from H₂O is attracted to the electronegative nitrogen atom in HCN. The bond dissociation energy for this hydrogen bond falls within the range of 8-42 kJ/mol.

**Hint:** Look for interactions involving hydrogen atoms bonded to electronegative atoms like O or N.

### Step 3: Conclusion
Based on the analysis, the only interaction that involves a hydrogen bond and has a bond dissociation energy between 8-42 kJ/mol is **H₂O · HCN**.

**Final Answer:** The correct interaction is **H₂O · HCN** (Option 4).