What happens to the value of the equilibrium constant (Kc) for a reaction if the reaction is reversed?

A.

It becomes zero

B.

It becomes negative

C.

It remains the same

D.

It becomes the reciprocal of the original value

Correct answer is D

If a reaction is reversed, the equilibrium constant (Kc) for the reversed reaction becomes the reciprocal of the original equilibrium constant. For a reaction:
A + B ⇌ C + D
The equilibrium constant Kc = [C][D]/[A][B]
For the reversed reaction:
C + D ⇌ A + B
The equilibrium constant Kc(reversed) = [A][B]/[C][D]
Thus, Kc(reversed) = 1/Kc.