Video Transcript
What is the direction of a reaction
when 𝐾 𝑐 is greater than one?
𝐾 𝑐 is the equilibrium constant
for concentration. The equilibrium constant for
concentration expresses the relationship between the reactant and product
concentrations at equilibrium. The value of the equilibrium
constant can indicate the direction of the equilibrium reaction. In this question, we want to know
the direction of a reaction when the equilibrium constant for concentration is
greater than one.
In its most basic form, the
equilibrium constant for concentration is calculated by dividing the concentration
of the products at equilibrium by the concentration of the reactants at
equilibrium. When the rate of the forward and
reverse reactions is the same, then the concentration of the reactants will be equal
to the concentration of the products. This will result in an equilibrium
constant of one.
When the rate of the forwards
reaction is greater than the rate of the reverse reaction, we say that the products
are favored and the equilibrium lies to the right. At equilibrium, there will be a
higher concentration of products than reactants. The numerator in the equation for
𝐾 𝑐 will be larger than the denominator, resulting in an equilibrium constant
greater than one.
When the rate of the reverse
reaction is greater than the rate of the forwards reaction, we say that the
reactants are favored and the equilibrium lies to the left. At equilibrium, there will be a
higher concentration of reactants than products. The denominator in the equation for
𝐾 𝑐 will be larger than the numerator, resulting in an equilibrium constant less
than one.
As this question is asking about a
reaction that has an equilibrium constant greater than one, we know that the
products are favored. So, we can say that the direction
of a reaction when 𝐾 𝑐 is greater than one is forward.
