Step-by-step explanation:
An equilibrium reaction is defined as the reaction in which the rate of forward reaction is equal to the rate of backward reaction.
For example, an equilibrium reaction between nitrogen, hydrogen and ammonia will be as follows.

Also, in an equilibrium mixture both reactants and products remain in the reaction mixture.
Therefore, we can conclude that in the given reaction mixture when equilibrium has been obtained then substances present in it will be
,
and
.