Which of the following is a heterogeneous mixture?

• A. Sugar dissolved in water
• B. Salad dressing (oil and vinegar)
• C. Air
• D. Table salt (NaCl)

Answer: (B)

Verified step by step guidance

1. Understand the definition of a heterogeneous mixture: it is a mixture where the components are not uniformly distributed and you can often see different parts or phases.
2. Examine each option to determine if the mixture is uniform (homogeneous) or non-uniform (heterogeneous):
3. Sugar dissolved in water forms a solution where sugar molecules are evenly distributed, making it a homogeneous mixture.
4. Air is a mixture of gases that are uniformly mixed, so it is also homogeneous.
5. Table salt (NaCl) is a pure compound, not a mixture, so it cannot be heterogeneous.
6. Salad dressing (oil and vinegar) consists of two liquids that do not mix uniformly, creating visible layers or droplets, which makes it a heterogeneous mixture.