Which of the following statement is (are) incorrect?

Options

A. 0.1 M KCl solution will have the same osmotic pressure as 0.1 M glucose solution
B. 0.1 M KCl solution will have the same boiling point as 0.1 M urea solution
C. 0.1 m glucose and 0.1 m urea are ismotic
D. 0.1 m `MgCl_(2)` solution will have less relative lowering of vapour pressure than 0.1 m NaCl

Answer

To determine which of the statements are incorrect, we will analyze each statement based on the principles of colligative properties, specifically osmotic pressure, boiling point elevation, and relative lowering of vapor pressure.

### Step 1: Analyze the first statement
**Statement A**: "0.1 molar KCl solution will have the same osmotic pressure as 0.1 molar glucose solution."

- **Osmotic Pressure Formula**: π = CRTI
- C = concentration
- R = gas constant
- T = temperature
- I = Van't Hoff factor (number of particles the solute dissociates into)

- For KCl:
- It dissociates into K⁺ and Cl⁻, so I = 2.

- For glucose:
- It does not dissociate, so I = 1.

- Since the Van't Hoff factors are different, the osmotic pressures will also be different. Therefore, this statement is **incorrect**.

### Step 2: Analyze the second statement
**Statement B**: "0.1 molar KCl solution will have the same boiling point as 0.1 molar urea solution."

- **Boiling Point Elevation Formula**: ΔTb = Kb * m * I
- Kb = ebullioscopic constant
- m = molality
- I = Van't Hoff factor

- For KCl:
- I = 2 (as it dissociates into 2 ions).

- For urea:
- I = 1 (as it does not dissociate).

- Since KCl has a higher Van't Hoff factor than urea, the boiling point elevation will be different. Therefore, this statement is **incorrect**.

### Step 3: Analyze the third statement
**Statement C**: "0.1 molar glucose and 0.1 molar urea are isoosmotic."

- Both glucose and urea do not dissociate, so:
- I = 1 for both.

- Since both solutions have the same concentration and the same Van't Hoff factor, they will have the same osmotic pressure. Therefore, this statement is **correct**.

### Step 4: Analyze the fourth statement
**Statement D**: "0.1 molar MgCl2 solution will have less relative lowering of vapor pressure than 0.1 molar NaCl."

- **Relative Lowering of Vapor Pressure**: Depends on the Van't Hoff factor.

- For MgCl2:
- It dissociates into Mg²⁺ and 2 Cl⁻, so I = 3.

- For NaCl:
- It dissociates into Na⁺ and Cl⁻, so I = 2.

- Since MgCl2 has a higher Van't Hoff factor than NaCl, it will have a greater relative lowering of vapor pressure. Therefore, this statement is **incorrect**.

### Conclusion
The incorrect statements are:
- Statement A
- Statement B
- Statement D

### Final Answer
**Incorrect Statements**: A, B, and D.

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