equilibrium refers to a reaction in which the reactants and products are in the same phase; equilbrium refers to a reaction in which the reactants and products are in different phases.

A

Reversible; Non-Reversible

B

Heterogeneous; Homogeneous

C

Reversible; Heterogeneous

D

Homogeneous; Heterogeneous

D. Homogeneous;Heterogeneous.

Explanation:

Homogeneous equilibrium refers to a reaction in which the reactants and products are in the same phase i.e whether gaseous or liquid. This means it's concentration reactants and products in a chemical reaction can vary over a wide range.

For example,

The Heterogeneous equilibrium refers to a reaction in which the reactants and products are in different phases i.e solid, gaseous, liquid or aqueous. Its position isn't dependent on the amounts of pure liquids or solids present in the reaction.

For example,

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.