Chemical equilibrium results if all reactants are used up. some products are removed. more reactants are added. forward reaction rate equals reverse reaction rate

Chemical equilibrium results if FORWARD REACTION RATE EQUALS REVERSE REACTION RATE.

In chemical reaction, chemical equilibrium refers to the phase, when the concentration of both reactants and products are constant with no observable change with time. This phase is typically reached, when the rate of forward reaction is equal to the rate of reverse reaction. Arrows that are pointing both ways are usually used in chemistry to indicate equilibrium reactions, the arrows implies that the reaction can move both ways, both backward and forward.

im not exactly sure but i think its b!

it is stable as it is in group 0 which have full outer shells of electrons