Question

what is the law of mass action for the reaction below? a ⇌ b k = a/b k = ab k = b/a

Explanation:

Step1: Recall Law of Mass Action

For a reversible reaction \( aA + bB
ightleftharpoons cC + dD \), the equilibrium constant \( K \) is \( K=\frac{[C]^c[D]^d}{[A]^a[B]^b} \). For \( A
ightleftharpoons B \), coefficients of \( A \) and \( B \) are 1.

Step2: Apply the Law

Products are in numerator, reactants in denominator. So \( K = \frac{[B]}{[A]} \).

Answer:

The third option (where \( K = \frac{[B]}{[A]} \))