When a liquid solidifies, generally there is

Options

A. decrease in enthalpy
B. decrease in entropy
C. increase in enthalpyincrease in entropy
D. none

Answer

To solve the question "When a liquid solidifies, generally there is a:", we will analyze the changes in enthalpy and entropy during the phase transition from liquid to solid.

### Step-by-Step Solution:

1. **Understanding the Phase Transition**:
- When a liquid solidifies, it undergoes a phase change from a liquid state to a solid state. This process is known as freezing or solidification.

2. **Defining Enthalpy and Entropy**:
- **Enthalpy (H)**: It is a measure of the total heat content of a system. During solidification, heat is released, which indicates a decrease in enthalpy.
- **Entropy (S)**: It is a measure of disorder or randomness in a system. A higher entropy value indicates a more disordered state. In the liquid state, molecules are more randomly arranged compared to the solid state.

3. **Analyzing the Change in Entropy**:
- In the liquid state, molecules are relatively free to move and are less ordered, leading to higher entropy.
- When the liquid solidifies, the molecules become more ordered and closely packed, resulting in a decrease in randomness. Therefore, the entropy decreases during solidification.

4. **Analyzing the Change in Enthalpy**:
- During the solidification process, the system releases energy (heat) to the surroundings. This release of energy indicates that the enthalpy of the system decreases.

5. **Conclusion**:
- When a liquid solidifies, there is a **decrease in enthalpy** and a **decrease in entropy**. Thus, the correct answer is that both enthalpy and entropy decrease.

### Final Answer:
When a liquid solidifies, there is a decrease in enthalpy and a decrease in entropy.

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