Phosphorus pentachloride decomposes according to the chemical equation pcl5(g)↽−−⇀pcl3(g)+cl2(=1.80 at 250 ∘c a 0.349 mol sample of pcl5(g) is injected into an empty 4.00 l reaction vessel held at 250 ∘c. calculate the concentrations of pcl5(g) and pcl3(g) at equilibrium.

Answer : The concentration of and at equilibrium are, 0.0834 M and 0.00385 M

Explanation :

First we have to calculate the concentration of .

The given equilibrium reaction is,

Initial conc.         0.08725         0           0

At equilibrium    (0.08725-x)     x           x

The expression for equilibrium constant will be,

Now put all the given values in this expression, we get:

By solving the term 'x', we get:

The concentration of at equilibrium = x = 0.0834 M

The concentration of at equilibrium = (0.08725-x) = (0.08725-0.0834) = 0.00385 M

Therefore, the concentration of and at equilibrium are, 0.0834 M and 0.00385 M