Question

The equilibrium-constant expression for a reaction written in one direction is the __________ of the one for the reaction written for the reverse direction.

Answer 1

• reciprocal

Step-by-step explanation:

The equilibrium constant for an equilibrium reaction is the ratio of the equilibrium constant for the forward reaction, Kf, to the equilibrium constant for the reverse reaction, Kr:

• For A ⇄ B

• The forward reaction is: A → B, with rate constant is Kf = K₁ and
• The reverse reaction is: B → A, with rate constant Kr = K₂

`K_(eq)=(K_f)/(K_r)=(K_1)/(K_2)`

When you write the reaction in the other reaction, the forward and the reverse reaction are exchanged:

• For B ⇄ A

• The forward reaction is B → A, with rate constant Kf = K₂
• The reverse reaction is A → B, with rate constant Kr = K₁

`K'_(eq)=(K_f)/(K_r)=(K_2)/(K_1)`

As you see:

`K'_(eq)=(1)/(K_(eq))`

Thus, the equilibrium-constant expression for a reaction written in one direction is the reciprocal___ of the one for the reaction written for the reverse direction.