The given question is incomplete. The complete question is:
A reversible reaction is said to have reached equilibrium when which of the following conditions is established?
a. concentration of reactants and products are equal
b. opposing reactions cease
c. speeds of opposite reactions become equal
d. temperature of opposite reactions become equal
Answer: c. speeds of opposite reactions become equal
Step-by-step explanation:
Equilibrium state is the state when reactants and products are present but the concentrations does not change with time.The state of equilibrium refers to the dynamic state as both forward and backwad reactions continue.
For a chemical equilibrium reaction, equilibrium state is achieved when the rate of forward reaction becomes equals to rate of the backward reaction.
Thus at chemical equilibrium, the amount of product and reactant remains constant because the rates of the forward and reverse reactions are equal.