Final answer:
The correct option is D.The statement that is not correct is that sodium chloride is a heterogeneous mixture; it is actually a compound and a pure substance.
Step-by-step explanation:
Sodium chloride, commonly known as table salt, is a compound composed of the elements sodium (Na) and chlorine (Cl). While compounds have different properties than their constituent elements, sodium chloride is indeed a pure substance, as all samples of sodium chloride are chemically identical.
Additionally, when sodium chloride is added to water, it forms a solution. A solution is a homogeneous mixture in which the solute (sodium chloride) is evenly distributed throughout the solvent (water). This compound is also a pure substance with a uniform and definite composition. When sodium chloride is added to water, it forms a homogeneous mixture or a solution, as the composition is uniform throughout. Hence, stating that sodium chloride is a heterogeneous mixture is not correct.