From the calculation, the equilibrium constant is obtained as 3. Option A
The term equilibrium constant shows the extent to which we could see the conversion of the reactants to products in a reaction system. Now we know that the equilibrium constant can be obtained by the use of the formula;
K = [H2] [I2]/[HI]^2
Now we have that at equilibrium;
[H2] = 0.5 M
[I2] = 1.5 M
[HI] = 0.5M
It then follows that;
K = 1.5 * 0.5/( 0.5)^2
K = 3
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