Polyhydroxy alcohols have higher boiling point than monohydric alcohols because :

Options

A. The former have more than one OH group
B. The former have higher moleculare weights
C. The former shows higher hydrogen bonding
D. The latter are more volatile

Answer

To understand why polyhydroxy alcohols have higher boiling points than monohydric alcohols, we can break down the reasoning into a series of steps:

### Step 1: Define Monohydric and Polyhydroxy Alcohols
- **Monohydric Alcohols**: These are alcohols that contain only one hydroxyl (-OH) group. Examples include methanol (CH3OH), ethanol (C2H5OH), and propanol (C3H7OH).
- **Polyhydroxy Alcohols**: These are alcohols that contain more than one hydroxyl (-OH) group. Examples include ethylene glycol (C2H6O2) and glycerol (C3H8O3).

### Step 2: Understand Hydrogen Bonding
- Hydrogen bonding occurs when a hydrogen atom covalently bonded to a highly electronegative atom (like oxygen) is attracted to another electronegative atom.
- Monohydric alcohols can form hydrogen bonds, but they can only form one hydrogen bond per molecule due to the presence of a single -OH group.

### Step 3: Compare Hydrogen Bonding in Monohydric and Polyhydroxy Alcohols
- Polyhydroxy alcohols, having multiple -OH groups, can form several hydrogen bonds with neighboring molecules. For example, glycerol can form multiple hydrogen bonds due to its three -OH groups.
- The presence of multiple hydrogen bonds in polyhydroxy alcohols leads to stronger intermolecular forces compared to monohydric alcohols.

### Step 4: Relate Hydrogen Bonding to Boiling Points
- The boiling point of a substance is influenced by the strength of the intermolecular forces. Stronger intermolecular forces result in higher boiling points.
- Since polyhydroxy alcohols have more hydrogen bonding interactions, they exhibit stronger intermolecular forces, which results in higher boiling points compared to monohydric alcohols.

### Conclusion
- Therefore, the reason polyhydroxy alcohols have higher boiling points than monohydric alcohols is due to the presence of multiple hydrogen bonds in polyhydroxy alcohols, leading to stronger intermolecular forces.

### Final Answer
Polyhydroxy alcohols have higher boiling points than monohydric alcohols because they show higher hydrogen bonding due to the presence of multiple -OH groups.

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