Which of the following are homogeneous solutions?

salt water, air and vinegar are homogeneous solutions.

Explanation:

A solution which consists of particles of same proportion is known as a homogeneous solution. Whereas a solution which consists of particles of different proportion is known as a heterogeneous solution.

Salt and water are homogeneous solutions as salt completely disperses in water and forms a clear solution as the particles of salt and water are in proportion.

Air is composed of different gases like nitrogen, oxygen etc are all mixed in fixed ratio. Therefore, air is a homogeneous mixture.

Sand and water are heterogeneous solution as the ration of mixing is different and more over sand particles can be separated from water. Thus, it is not a homogeneous mixture.

Vinegar is also a homogeneous solution as it is composed of acetic acid and water which are mixed in fixed proportion.

Cement is a heterogeneous mixture as it is composed of a number of different substances mixed in different proportions.

Thus, we can conclude that salt water, air and vinegar are homogeneous solutions.