Dipole-induced dipole interaction are present in which of the following pairs

Options

A. `SiF_4` & He atoms
B. `H_2O` and alcohol
C. `CI_2 and C C I_4`
D. HF and He atom

Answer

To determine which pairs exhibit dipole-induced dipole interactions, we need to understand the nature of these interactions. Dipole-induced dipole interactions occur between a polar molecule (which has a permanent dipole) and a non-polar molecule (which does not have a permanent dipole).

### Step-by-Step Solution:

1. **Identify Polar and Non-Polar Molecules**:
- A polar molecule has a permanent dipole due to differences in electronegativity between the atoms (e.g., H2O, HF).
- A non-polar molecule lacks a permanent dipole (e.g., Cl2, CH4, He).

2. **Analyze the Given Pairs**:
- **H2O (water)**: This is a polar molecule due to the electronegativity difference between oxygen and hydrogen.
- **Alcohol (ROH)**: Alcohols are also polar due to the presence of the hydroxyl (-OH) group.
- **Cl2 (chlorine gas)**: This is a non-polar molecule since both chlorine atoms have the same electronegativity.
- **CCl4 (carbon tetrachloride)**: This molecule is symmetrical and non-polar.
- **He (helium)**: This is a noble gas and is non-polar.
- **HF (hydrogen fluoride)**: This is a polar molecule due to the electronegativity difference between hydrogen and fluorine.
- **SiF4 (silicon tetrafluoride)**: This molecule is symmetrical and non-polar.

3. **Determine Interactions**:
- **H2O and He**: The polar H2O can induce a dipole in the non-polar He.
- **Alcohol and He**: The polar alcohol can induce a dipole in the non-polar He.
- **HF and He**: The polar HF can induce a dipole in the non-polar He.
- **Cl2 and H2O**: No interaction since both are polar.
- **CCl4 and H2O**: No interaction since CCl4 is non-polar.
- **SiF4 and He**: No interaction since both are non-polar.

4. **Conclusion**:
- The pairs that exhibit dipole-induced dipole interactions are:
- HF and He
- H2O and He
- Alcohol and He

### Final Answer:
The dipole-induced dipole interactions are present in the pairs: **HF and He**, **H2O and He**, and **Alcohol and He**.

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