Which solution will have the highest b.p. ?

Options

A. `1%` solution of `C_(6)H_(12)O_(6)`
B. `1%` solution of NaCl
C. `1%` solution of `ZnSO_(4)`
D. `1%` solution of `(NH_(2))CO`

Answer

To determine which solution will have the highest boiling point among the given options (1% glucose, 1% NaCl, 1% zinc sulfate, and 1% copper(II) sulfate), we can use the formula for boiling point elevation:

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

Where:
- \(\Delta T_b\) is the boiling point elevation,
- \(i\) is the van 't Hoff factor (the number of particles the solute breaks into),
- \(K_b\) is the ebullioscopic constant (which is constant for a given solvent),
- \(m\) is the molality of the solution.

### Step 1: Identify the van 't Hoff factor (i) for each solute.
1. **Glucose (C6H12O6)**:
- Glucose is a non-electrolyte and does not dissociate in solution.
- Therefore, \(i = 1\).

2. **Sodium Chloride (NaCl)**:
- NaCl dissociates into two ions: Na\(^+\) and Cl\(^-\).
- Therefore, \(i = 2\).

3. **Zinc Sulfate (ZnSO4)**:
- Zinc sulfate dissociates into three ions: Zn\(^{2+}\) and SO\(_4^{2-}\).
- Therefore, \(i = 2\) (though it may not dissociate completely, we consider the maximum possible dissociation for this calculation).

4. **Copper(II) Sulfate (CuSO4)**:
- Copper(II) sulfate also dissociates into three ions: Cu\(^{2+}\) and SO\(_4^{2-}\).
- Therefore, \(i = 2\).

### Step 2: Compare the boiling point elevation for each solution.
- **Glucose**:
\[ \Delta T_b = 1 \cdot K_b \cdot m \]

- **NaCl**:
\[ \Delta T_b = 2 \cdot K_b \cdot m \]

- **Zinc Sulfate**:
\[ \Delta T_b = 2 \cdot K_b \cdot m \]

- **Copper(II) Sulfate**:
\[ \Delta T_b = 2 \cdot K_b \cdot m \]

### Step 3: Determine which solution has the highest boiling point.
Since both NaCl, Zinc sulfate, and Copper(II) sulfate have the same van 't Hoff factor of 2, they will all have a higher boiling point than glucose, which has a van 't Hoff factor of 1. However, since NaCl completely dissociates into two ions, while zinc sulfate and copper(II) sulfate may not fully dissociate, we can conclude that:

- **NaCl** will have the highest boiling point among the given solutions.

### Final Answer:
The solution with the highest boiling point is the **1% NaCl solution**.

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