Dissolving salt in water is generally considered what type of change?

Correct answer: Physical change

The direct answer is D: dissolving salt in water is generally a physical change. A physical change alters the form, distribution, or state of a substance without producing a new substance. When salt dissolves, its ions become distributed among water molecules. Under suitable conditions, water can be removed by evaporation and the salt can be obtained again, so the change is usually treated as reversible and physical at school level. Option A is wrong because a nuclear change involves the atomic nucleus, which does not happen when ordinary salt dissolves. Option B is wrong because dissolving salt does not turn it into a metal or represent a metallic change. Option C is wrong because optical change concerns light-related behaviour, not the basic classification of salt dissolving. Option D is correct because the substances can be recovered and no new chemical identity is normally required to explain the process. A helpful memory cue is: recoverable by evaporation usually points to a physical change, though unusual chemical reactions must be judged separately.