At 450K, Kp= 2.0 × 1010 bar for the given reaction at equilibrium.
2SO2(g) + O2(g) ⇌2SO3 (g)
What is Kcat this temperature?
We know that,
Kp = Kc[RT]Δn
Where Δn is number of gas molecule in products minus number of gas molecule in reactant in balanced chemical equation.
For reaction,
2SO2(g) + O2(g) ⇌2SO3 (g)
Δn = 2 – 3 = 1
T = 450 K
Kp= 2.0 × 1010 bar
Kc =
Kc = 
= 53.48 × 107 L mol-1
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