I'm brushing up and the example in my book is against my intuition.
A buffer solution contains 1.0 mol/L acetic acid and 1.0 mol/L sodium acetate. The solution is at pH = pKa = 4.75. What's the pH after addition of 0.01 mol/L HCl?
They don't write how much of the acid is added.
They go on stating that addition of x = 0.01 mol/L H+ results in pH = 4.75 - log[(1.01 mol/L) / (0.99 mol/L)] = 4.733.
That's all fine from the formalism. What's against my intuition is:
Why is it not required to state how much of the acid was added? Given the buffer solution, is the outcome of adding acid the same independent if I add a Liter of if I add a mL?