When solid NaCl is stirred into water, which type of change occurs?

• A. A physical change, because NaCl dissolves but its chemical composition remains the same.
• B. No change occurs, because NaCl does not interact with water.
• C. A chemical change, because NaCl reacts with water to form a new substance.
• D. A nuclear change, because the nuclei of Na and Cl atoms are altered.

Answer: (A)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: A physical change affects the form of a substance but not its chemical identity, while a chemical change results in the formation of new substances with different chemical compositions.
2. Consider what happens when NaCl (table salt) dissolves in water: The solid NaCl dissociates into Na⁺ and Cl⁻ ions, but these ions remain chemically the same as in the solid form.
3. Recognize that dissolving is a physical process because the chemical composition of NaCl does not change; it simply disperses into ions in the water.
4. Eliminate options that describe chemical or nuclear changes, since no new substances are formed and the nuclei of atoms remain unchanged during dissolution.
5. Conclude that the correct classification of the change when NaCl dissolves in water is a physical change.