Which of the following is true regarding dissolution of `NH_(4)Cl` in water?

Options

A. It is an endothermic and chemical change.
B. It is an exothermic and physical change.
C. It is an endothermic and physical change.
D. It is an exothermic and chemical change.

Explanation

To determine which statement is true regarding the dissolution of NH₄Cl (ammonium chloride) in water, we can analyze the process step by step.

### Step-by-Step Solution:

1. **Understanding Dissolution**:
- When NH₄Cl is added to water, it dissolves to form ions. The dissolution process can be represented as:
\[ NH_4Cl (s) \rightarrow NH_4^+ (aq) + Cl^- (aq) \]
- This indicates that solid ammonium chloride dissociates into ammonium ions (NH₄⁺) and chloride ions (Cl⁻) in the aqueous solution.

2. **Identifying the Type of Change**:
- **Chemical Change vs. Physical Change**:
- A **chemical change** involves the formation of new substances, while a **physical change** involves changes in the state of a substance without forming new products.
- In this case, although NH₄Cl dissociates into ions, it does not form new substances that are chemically different from the original compound. Therefore, this process is considered a **physical change**.

3. **Determining the Thermodynamic Nature**:
- **Endothermic vs. Exothermic**:
- An **endothermic reaction** absorbs heat from the surroundings, while an **exothermic reaction** releases heat.
- The dissolution of NH₄Cl in water is known to be an endothermic process because it absorbs heat from the surroundings, resulting in a drop in temperature of the solution.

4. **Conclusion**:
- Based on the analysis, the dissolution of NH₄Cl in water is a **physical change** that is **endothermic**.

### Final Answer:
The correct statement regarding the dissolution of NH₄Cl in water is that it is an **endothermic physical change**.