The enthalpy change for the reaction,
`H_2 O_((s))to H_2 O_((l)),Delta H=+6.01 kJ mol^(-1) at 0^@C` is called enthalpy of _______ .

Options

A. vaporization
B. fusion
C. combustion
D. solution

Answer

To solve the question regarding the enthalpy change for the reaction where solid water (ice) is converted to liquid water, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction**: The reaction given is:
\[ H_2O_{(s)} \rightarrow H_2O_{(l)} \]
This represents the phase change from solid water (ice) to liquid water.

2. **Understand the Enthalpy Change**: The enthalpy change (\(\Delta H\)) for this reaction is given as:
\[ \Delta H = +6.01 \, \text{kJ mol}^{-1} \text{ at } 0^\circ C \]
This positive value indicates that heat is absorbed during the process, which is characteristic of melting.

3. **Define the Term**: The enthalpy change associated with the transition from solid to liquid is known as the enthalpy of fusion. This term specifically refers to the heat required to melt a solid at its melting point.

4. **Eliminate Other Options**:
- **Enthalpy of Vaporization**: This refers to the heat required to convert a liquid into a vapor, which is not applicable here.
- **Enthalpy of Combustion**: This is the heat released when a substance combusts in oxygen, also not relevant for this phase change.
- **Enthalpy of Solution**: This refers to the heat change when a solute dissolves in a solvent, which does not apply to the solid-liquid transition.

5. **Conclusion**: Therefore, the enthalpy change for the reaction where solid water is converted to liquid water is called the enthalpy of fusion.

### Final Answer:
The enthalpy change for the reaction \( H_2O_{(s)} \to H_2O_{(l)} \) is called the enthalpy of **fusion**.

---