Glycerol (propane-1, 2, 3-triol) is more viscous than ethylene glycol (ethane-1, 2-diol).

Explanation

To explain why glycerol (propane-1,2,3-triol) is more viscous than ethylene glycol (ethane-1,2-diol), we will analyze their structures and the implications for hydrogen bonding.

### Step-by-Step Solution:

1. **Identify the Structures**:
- Glycerol (propane-1,2,3-triol) has the chemical structure:
\[
\text{CH}_2\text{OH} - \text{CHOH} - \text{CH}_2\text{OH}
...