Which one of the following compounds shows the presence of intramolecular hydrogen bond?

Options

A. Cellulose
B. Concentrated acetic acid
C. `H_2O_2`
D. HCN

Explanation

To determine which of the given compounds shows the presence of intramolecular hydrogen bonding, we need to analyze each compound based on the definition of intramolecular hydrogen bonding. Intramolecular hydrogen bonding occurs within a single molecule, where a hydrogen atom is attracted to an electronegative atom (like oxygen or nitrogen) within the same molecule, forming a bond.

### Step-by-Step Solution:

1. **Understand Intramolecular vs. Intermolecular Hydrogen Bonding**:
- Intramolecular hydrogen bonding occurs within a single molecule.
- Intermolecular hydrogen bonding occurs between different molecules.

2. **Analyze the Compounds**:
- **Cellulose**: Cellulose is a polymer made up of long chains of glucose units. In its structure, there are hydroxyl (–OH) groups that can participate in hydrogen bonding within the same molecule. This can lead to the formation of intramolecular hydrogen bonds.
- **Concentrated Acetic Acid**: The structure of acetic acid does not form a stable ring structure that would allow for intramolecular hydrogen bonding. The hydrogen bonding occurs between different acetic acid molecules (intermolecular).
- **Hydrogen Peroxide (H2O2)**: While H2O2 can form hydrogen bonds, these are primarily intermolecular due to the lack of a stable intramolecular structure that would allow for such bonding.
- **Hydrogen Cyanide (HCN)**: HCN does not have the necessary structure to form intramolecular hydrogen bonds as it lacks the required electronegative atoms in a suitable arrangement.

3. **Conclusion**:
- Based on the analysis, **Cellulose** is the compound that shows the presence of intramolecular hydrogen bonding due to its structure allowing for hydrogen bonds within the same molecule.

### Final Answer:
**Cellulose shows the presence of intramolecular hydrogen bonding.**