Which of the following liquids has the highest viscosity ?

Options

A. Benzene
B. Carbon disulphide
C. Acetone
D. Ethanol

Answer

To determine which of the given liquids has the highest viscosity, we need to analyze the intermolecular forces present in each liquid. Viscosity is defined as the resistance of a liquid to flow, and it is influenced by the strength of intermolecular forces. The stronger the intermolecular forces, the higher the viscosity.

### Step-by-Step Solution:

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

2. **Identifying the Liquids**:
- The liquids given are:
- A) Benzene (C6H6)
- B) Carbon disulfide (CS2)
- C) Acetone (C3H6O)
- D) Ethanol (C2H5OH)

3. **Analyzing Intermolecular Forces**:
- **Benzene**:
- Contains London dispersion forces.
- **Carbon Disulfide**:
- Also primarily has London dispersion forces.
- **Acetone**:
- Has dipole-dipole interactions and London dispersion forces.
- **Ethanol**:
- Exhibits hydrogen bonding (a strong type of dipole-dipole interaction) due to the presence of an -OH group.

4. **Comparing Viscosity**:
- Since viscosity increases with stronger intermolecular forces, we can compare:
- Benzene and carbon disulfide have weak London dispersion forces.
- Acetone has stronger dipole-dipole interactions than benzene and carbon disulfide.
- Ethanol has hydrogen bonding, which is significantly stronger than the other forces present in the other liquids.

5. **Conclusion**:
- Among the given liquids, ethanol has the highest viscosity due to the presence of hydrogen bonding, which is the strongest intermolecular force among the options provided.

### Final Answer:
**Ethanol (C2H5OH) has the highest viscosity among the given liquids.**

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