Question

which of these is not a homogeneous mixture?
o sugar dissolved in water
o a silver mercury amalgam used to fill a tooth cavity
o oxygen and nitrogen gases in the air
o oil and vinegar salad dressing

Explanation:

A homogeneous mixture has uniform composition throughout. Sugar - water is a solution, silver - mercury amalgam is a homogeneous alloy, and air is a homogeneous gas mixture. Oil and vinegar salad dressing separates into layers as oil is non - polar and vinegar is polar, making it a heterogeneous mixture.

Answer:

oil and vinegar salad dressing