For which of the following can the composition vary?

a. both homogeneous and heterogeneous mixtures

b. heterogeneous mixture

c. homogeneous mixture

d. element pure substance

Option a. both homogeneous and heterogeneous mixture.

Explanation:

This can be explained as a mixture is the combination of more than one substances mixed together while retaining their identities or chemical properties.

Homogeneous mixtures in which the components are mixed in the same amounts or proportion, i. e., it has uniformity in it. Heterogeneous mixtures in which the constituents are not mixed in uniform proportion and are separable. Pure elements are those which have the a stable isotope or the atomic number of which are same. Thus the composition can only vary in homogeneous and heterogeneous mixtures.

Answer: Option (a) is the correct answer.

Explanation:

A homogeneous mixture is defined as a mixture that contains evenly distributed solute particles into the solvent.

For example, NaCl dissolved in water is a homogeneous solution.

On the other hand, a solution in which solute particles are not evenly distributed into the solvent is known as a heterogeneous mixture.

For example, when sand is added to water then it forms a heterogeneous solution.

Thus, we can conclude that for both homogeneous and heterogeneous mixtures the composition vary.