For the equilibrium reaction H₂(g) + I₂(g) ⇄ 2HI(g), the initial concentrations of H₂ and I₂ were both 1 M. At equilibrium, the concentration of HI is 1.2 M. Calculate the equilibrium constant Kc.
- 4
- 9
- 16
- 2.25
📝 Detailed explanation
Initial: [H₂]=1, [I₂]=1, [HI]=0.Change: [HI] gains 1.2, so [H₂] and [I₂] both lose 1.2/2 = 0.6.
Equilibrium: [HI]=1.2, [H₂]=1-0.6=0.4, [I₂]=1-0.6=0.4.
Kc = [HI]² / ([H₂][I₂]) = (1.2)² / (0.4 * 0.4) = 1.44 / 0.16 = 9.