Equilibrium Constants


Chemical equilibrium

In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations that have no further tendency to change with time.
In an equilibrium state at a constant temperature, the ratio of the reactant’s concentration product to the product’s concentration product is always constant. This is called the law of chemical equilibrium.

In general, the equilibrium constant ‘K’ value is the product’s ratio to the reactant.
Assuming that the following reaction is in equilibrium,

\[ aA+bB\rightleftharpoons cC+dD \]

The forward reaction speed and the backward reaction speed are the same.
And the equilibrium constant K can be obtained as follows.

\[ k=\frac { { [C] }^{ c }{ [D] }^{ d } }{ { [A] }^{ a }{ [B] }^{ b } } \]

The equilibrium constant ‘K’ always shows a constant value at a constant temperature.

What can be known by equilibrium constants

The K value tells you what chemical reaction is going to happen in the future.
If the current value is less than the K value, a forward reaction will occur. On the contrary, if it is big, the backward reaction will happen.
If the current value is equal to the K value, the equilibrium state is reached.