Textbook Question 7.23

[Sofia Lucido 3L]

For part b of textbook problem 7.23 I am wondering why the solutions manual found K (the equilibrium constant) to be
I set up K the inverse of that expression because I thought we use K for the reverse reaction of the equilibrium? Can someone explain?

[Gina Spagarino 3G]

Hi, that is the K of the fast step 1, to use the pre-equiliibrium approach to substitute in for step 2 the slow step. It is set up for step 1 as [products]/[reactants], as K usually is... because K also equals k/k', then solving for [HClO-] allows it to be substituted out of step 2 since it is an intermediate and therefore should not be in the rate law.

[Nico Medina]

I was wondering this too, thanks for the help!