Which of these scenarios involve a reaction that is at equilibrium?
a. the reaction is producing reactants and products at an equal rate.
b. the reaction is producing more reactants than products.
c. the reaction is only producing products
d. the reaction is producing more products than reactants.

a. the reaction is producing reactants and products at an equal rate. is the  correct answer.

Explanation:

If a reaction is at equilibrium then the reaction rates for both the reverse and forward directions are equal.

catalyst that increases the reaction rate of a  reaction, but it does not change the equilibrium state for that reaction.

Thus at the equilibrium stage, the concentration of the reactants and the product remain constant.

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.