Question

Consider an exothermic process for the hypothetical reaction A <=> B

 

A.  A.Which rate constant, kf or kb (k1 or k-1) is larger and how do you know? 

B. If one rate constant is larger than the other, how does the system ever reach equilibrium?

Answer 1

A) From equillibrium constant K_eq we can know which rate constant (k1 or k-1)

because

k1/k-1 = K_eq

If equillibrium constant is less than 1 larger rate constant is K-1

If equillibrium constant is greater than 1 larger rate constant is k1

A) when rate of farward reaction is equal to the rate of reverse reaction the equillibrium is reached

A <-----> B

rate of farward reaction = k1[A]

rate of backward reaction = k-1[B]

k1[A] = k-1[B]

k1/k-1 = [B]/[A]

K_eq = [B]/[A]