Which of the most viscous ?

Options

A.
B.
C.
D.

Explanation

To determine which compound is the most viscous among the given options, we need to consider the concept of viscosity and its relationship with hydrogen bonding in alcohols and phenols.

### Step-by-Step Solution:

1. **Understand Viscosity**:
- Viscosity is a measure of a fluid's resistance to flow. Higher viscosity means the fluid is thicker and flows less easily.

2. **Identify Factors Affecting Viscosity**:
- The primary factor affecting the viscosity of alcohols and phenols is the presence of hydroxyl (–OH) groups. More hydroxyl groups lead to stronger hydrogen bonding, which increases viscosity.

3. **Analyze the Given Compounds**:
- Let's consider the given compounds:
- Compound A: Has 2 –OH groups.
- Compound B: Propane-1,3-triol (glycerol) has 3 –OH groups.
- Compound C: Phenol has 1 –OH group.

4. **Count the –OH Groups**:
- Compound A: 2 –OH groups
- Compound B: 3 –OH groups
- Compound C: 1 –OH group

5. **Determine the Hydrogen Bonding**:
- More –OH groups mean more hydrogen bonding.
- Compound B (Propane-1,3-triol) with 3 –OH groups will have the most hydrogen bonding.

6. **Conclusion**:
- Since Compound B has the highest number of –OH groups, it will be the most viscous among the options provided.

### Final Answer:
- The most viscous compound is **Compound B (Propane-1,3-triol)**.