The boiling point of water ,ethyl alcohol and diethyl ether are 100°C , 78.5°C and 34.6°C respectively. Intermolecular forces will be in order of

Options

A. Water gt Ethyl alcohol gt Diethyl ether
B. Ethyl alcohol gt Water gt Diethyl ether
C. Diethyl ether gt Ethyl alcohol gt Water
D. Diethyl ether gt Water gt Ethyl alcohol

Answer

To determine the order of intermolecular forces in water, ethyl alcohol, and diethyl ether based on their boiling points, we can follow these steps:

### Step 1: Identify the boiling points
- Water: 100°C
- Ethyl alcohol: 78.5°C
- Diethyl ether: 34.6°C

### Step 2: Understand the relationship between boiling point and intermolecular forces
The boiling point of a substance is indicative of the strength of its intermolecular forces. Higher boiling points suggest stronger intermolecular forces because more energy (in the form of heat) is required to break these forces and convert the liquid into vapor.

### Step 3: Analyze the types of intermolecular forces present
- **Water (H2O)**: Water exhibits strong hydrogen bonding due to the presence of highly electronegative oxygen atoms bonded to hydrogen atoms. This leads to very strong intermolecular attractions.

- **Ethyl alcohol (C2H5OH)**: Ethyl alcohol also exhibits hydrogen bonding due to the hydroxyl (-OH) group. However, the presence of the ethyl group (C2H5) reduces the overall strength of hydrogen bonding compared to water.

- **Diethyl ether (C2H5OC2H5)**: Diethyl ether has weaker intermolecular forces. Although it has an oxygen atom, it does not have hydrogen bonding like water and ethyl alcohol because it lacks an -OH group. Instead, it primarily exhibits dipole-dipole interactions and London dispersion forces.

### Step 4: Rank the substances based on boiling points
Based on the boiling points and the types of intermolecular forces:
1. Water (100°C) - Strongest intermolecular forces (hydrogen bonding).
2. Ethyl alcohol (78.5°C) - Moderate intermolecular forces (hydrogen bonding, but weaker than water).
3. Diethyl ether (34.6°C) - Weakest intermolecular forces (mostly dipole-dipole and dispersion forces).

### Conclusion
The order of intermolecular forces from strongest to weakest is:
**Water > Ethyl Alcohol > Diethyl Ether**