A 100.0 mL sample of 0.10 M #NH_3# is titrated with 0.10 M #HNO_3#. How do you determine the pH of the solution after the addition of 40.0 mL of #HNO_3#?. The Kb of NH3 is 1.8 × 10-5.?
You can do it like this:
As the acid is added to the base the following neutralisation takes place:
The initial moles of
The number of moles of
From the equation you can see that the acid and base react in a molar ratio of 1:1.
So the no. moles of
The total volume is now
The concentration of
From an ICE table we get the expression:
Where b is the concentration of the base.
We can approximate this to the initial concentration since the dissociation is small.
Putting in the numbers: