Question

One mole of ab reacts with one mole of cd then equilibrium constant

Answer 1

To calculate an equilibrium constant the reaction must be a reversible reaction.

Let's consider A+B=C a reversible reaction.

Let the initial concentrations of A and B be '1'. There will be ‘0’ concentration of product as the state is initial.

Now at equilibrium, the concentration of A and B changes to '1-x', as product produces is referred to be 'x'.

As we know, the product is of two moles therefore x=2…

Now, Equilibrium constant (k) is the ratio of product of concentration of product to the product of concentration of reactants at equilibrium.

K = [C]² / [A][B]

K = x² / (1-x)(1-x)

K = 2² / (1–2)(1–2)

So, K=4

The unit of Equilibrium constant depends upon the product and ​reactants, therefore in this case there is no unit.