Find the equilibrium constant (Kc) at 500 K for:

2HI(g) ⇌ H₂(g) + I₂(g)

given that:

½H₂(g) + ½I₂(g) ⇌ HI(g), Kc = 5
 

1. 0.04

2. 0.4

3. 25

4. 2.5