chemistry help needed please.....

Question

When  2 moles of HCl is added to 1 litre of an  acidic buffer ,its pH changes from 3.4 to 2.9 . The buffer capacity of the buffer solution is ?

 

1.   8
2.   4
3.   0
4.   2

Answer 1

The buffer capacity,β, will be equal to the number of moles of H⁺ added per liter of buffer divided by the change in pH:

 

β = (2 mol/L)/(0.5) = 4.  The answer is #2