Salt water is classified as a homogeneous mixture. This means that the components of salt water, which are salt (sodium chloride) and water, are not only mixed together but are also evenly distributed throughout the solution.
When salt is added to water, it dissolves, breaking down into its constituent ions (sodium and chloride ions). Because these ions are uniformly distributed in the water, the salt water appears as a single substance, without any distinct layers or particles. This even distribution of components is what characterizes a homogeneous mixture.
If salt water were a heterogeneous mixture, we would see distinct portions or layers of salt and water, which is not the case here. In summary, since salt water has a uniform composition throughout, it is accurately classified as a homogeneous mixture.