1. In an equilibrium, A + B ---> C + D;

"A" & "B" are mixed in a vessel at temperature "T". The initial concentration of "A" was twice the initial concentration of "B", & after the equilibrium has reached, concentration of "C" was twice the equilibrium concentration of "B". What is the value of "Kc"?

To find the value of Kc, we need to use the equilibrium concentrations of the species involved in the reaction.

Let's assume the initial concentration of B is x. Since the initial concentration of A is twice that of B, it would be 2x.

At equilibrium, the concentration of C is twice the equilibrium concentration of B. Let's say the equilibrium concentration of B is y. Therefore, the concentration of C would be 2y.

The balanced chemical equation is: A + B ---> C + D

Now, we can set up the expression for Kc using the equilibrium concentrations:

Kc = ([C] * [D]) / ([A] * [B])

Since the concentrations of D and A are not given in the question, we will simplify the expression based on the information available.

Kc = (2y * [D]) / (2x * y)

Kc = [D] / x

As you can see, the value of Kc depends on the equilibrium concentration of species D. Without more information about D or the reaction conditions, we cannot determine the exact value of Kc with the given information.