Which is the correct form of equilibrium expression of the following reaction.

Question

2PbS(s)+3O2(g)reverse arrow 2PbOs + 2SO2g

Why is the answer
Kc= SO2 power 2/O2 power 3

Why in particular is this the arrangement for equilibrium expression?

Thank you

Answer 1

Your way of wording the question is confusing. IF YOU MEAN,
2PbS(s) + 3O2(g) <== 2PbO(s) + 2SO2(g)
then Keq = produces/reactants and the equation is reversed from the usual direction.
So Keq = (O2)^3/(SO2)^2
The "reverse arrow" part is the confusing part. Write the arrow the way the reaction is given instead of using words.