A solution of 1 molal concentration of a solute will have maximum boiling point elevation when the solvent is

Options

A. Ethyl alcohol
B. Acetone
C. Benzene
D. Chloroform

Answer

To determine which solvent will provide the maximum boiling point elevation for a 1 molal solution of a solute, we can use the formula for boiling point elevation:

\[ \Delta T_b = K_b \cdot m \]

Where:
- \(\Delta T_b\) is the boiling point elevation.
- \(K_b\) is the ebullioscopic constant of the solvent.
- \(m\) is the molality of the solution.

Given that the molality \(m\) is constant at 1 molal for all solvents, the boiling point elevation \(\Delta T_b\) will depend solely on the value of \(K_b\). Therefore, to find the solvent that provides the maximum boiling point elevation, we need to identify which solvent has the highest \(K_b\) value.

### Step-by-Step Solution:

1. **Identify the solvents and their \(K_b\) values**:
- Ethyl alcohol (C₂H₅OH)
- Acetone (CH₃COCH₃)
- Benzene (C₆H₆)
- Chloroform (CHCl₃)

2. **Research or recall the \(K_b\) values**:
- \(K_b\) for Ethyl alcohol: approximately 1.2 °C kg/mol
- \(K_b\) for Acetone: approximately 0.3 °C kg/mol
- \(K_b\) for Benzene: approximately 2.5 °C kg/mol
- \(K_b\) for Chloroform: approximately 3.6 °C kg/mol

3. **Compare the \(K_b\) values**:
- Ethyl alcohol: 1.2
- Acetone: 0.3
- Benzene: 2.5
- Chloroform: 3.6

4. **Determine the maximum \(K_b\)**:
- The highest \(K_b\) value is for Chloroform (3.6 °C kg/mol).

5. **Conclusion**:
- Since \(\Delta T_b\) is directly proportional to \(K_b\), the solvent that will provide the maximum boiling point elevation for a 1 molal solution of a solute is Chloroform.

### Final Answer:
The solvent that will provide the maximum boiling point elevation for a 1 molal concentration of a solute is **Chloroform (CHCl₃)**.

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