Ammonia (#NH_3#) is a weak base with a #K_b = 1.8 x 10^-5#. What is the balanced chemical equation for the reaction of ammonia with water. Using the I.C.E the method, calculate the pH and ionization of a 1.75 M #NH_3# solution in 2.50 M #NH_4Cl#?
Ammonia is a weak base and ionises in water:
These are equilibrium concentrations.
The ICE table in mol/l is:
Because the value of
This means we can assume that the initial concentrations are a good enough approximation to those at equilibrium.
There is therefore, no need to set up an ICE table. You can just use the equation for
Rearranging the expression for