NH3 Addition to NH4Cl Solution
Given is a 0.001 molar NH4Cl solution. What is the pH after addition of 0.2 mmol NH3 per liter?
We start with pure water (button H2O) and add two reactants (button Reac, and activate checkbox “More reactions”):
If you click on Start the calculated pH value is shown (see screenshot on the right):
|pH = 8.55|
Note. In equilibrium thermodynamics, the order in which we add the reactants does not play a role. We can first add NH4Cl and then NH3 or vice versa – the final result is the same (even if different intermediate states are passed through):
|first NH4Cl, then NH3:||pH = 7.00 → 6.13 → 8.55|
|first NH3, then NH4Cl:||pH = 7.00 → 9.71 → 8.55|
Here, NH4Cl acts as acid and NH3 as base.