Statement-I : Molal elevation constant depends on the nature of solvent.
Because
Statement-II: Molal elevation constant is the elevation in boiling point when 1 mole of the solute is dissolved in 1 kg of solvent.

Answer

To solve the question regarding the statements about the molal elevation constant, we will analyze each statement step by step.

### Step 1: Analyze Statement I
**Statement I:** "Molal elevation constant depends on the nature of solvent."

- The molal elevation constant (Kb) is a property that is specific to each solvent. It indicates how much the boiling point of a solvent will increase when a solute is added.
- The value of Kb varies with different solvents due to differences in their molecular structure, intermolecular forces, and other physical properties.

**Conclusion for Statement I:** True. The molal elevation constant does depend on the nature of the solvent.

### Step 2: Analyze Statement II
**Statement II:** "Molal elevation constant is the elevation in boiling point when 1 mole of the solute is dissolved in 1 kg of solvent."

- The molal elevation constant (Kb) is defined in the context of colligative properties, specifically boiling point elevation.
- The formula for boiling point elevation is given by:
\[ \Delta T_b = K_b \cdot m \]
where \(\Delta T_b\) is the elevation in boiling point, \(K_b\) is the molal elevation constant, and \(m\) is the molality of the solution.
- By definition, molality (m) is defined as the number of moles of solute per kilogram of solvent. Therefore, when 1 mole of solute is dissolved in 1 kg of solvent, the molality is 1 mol/kg, which directly relates to the definition of Kb.

**Conclusion for Statement II:** True. The statement accurately describes the definition of the molal elevation constant.

### Step 3: Determine the Relationship Between Statements
- While both statements are true, Statement II does not provide a correct explanation for Statement I.
- Statement I discusses the dependence of Kb on the solvent, while Statement II describes the definition of Kb without addressing why it depends on the solvent's nature.

### Final Conclusion
- **Statement I:** True
- **Statement II:** True
- **Relationship:** Statement II is not the correct explanation for Statement I.