A solution is prepared by dissolving 0.23 mol of chloroacetic acid and 0.27 mol of sodium chloroacetate in watersufficient to yield 1.00 L of solution. The addition of 0.05 mol of HCl to this buffer solution causes the pH to dropslightly. The pH does not decrease drastically because the HCl reacts with the __________ present in the buffersolution. The Ka of chloroacetic acid is 1.36 × 10-3.

Some aspects of aqueous equilibria are: The common ion effect: Adding a strong electrolyte with an ion in common with a weak electrolyte decreases the dissociation of the weak electrolyte. The buffer region: Before the equivalence point, the solution contains a mixture of a weak acid and its salt. This is also known as the buffer region of the curve. The equivalence point: At the equivalence point, the moles of acid equal the moles of base. The solution contains only water and the salt from the cation of the base and the anion of the acid. Adding a strong electrolyte with an ion in common... Show more

Some aspects of aqueous equilibria are:
The common ion effect: Adding a strong electrolyte with an ion in common with a weak electrolyte decreases the dissociation of the weak electrolyte.
The buffer region: Before the equivalence point, the solution contains a mixture of a weak acid and its salt. This is also known as the buffer region of the curve.
The equivalence point: At the equivalence point, the moles of acid equal the moles of base. The solution contains only water and the salt from the cation of the base and the anion of the acid. Adding a strong electrolyte with an ion in common with a reaction system at equilibrium shifts the equilibrium to reduce the concentration of the common ion.
The pH: From the start of the titration to near the equivalence point, the pH increases slowly. Just before and after the equivalence point, the pH increases rapidly. At the equivalence point, the pH is given by the salt solution, which is pH = 7.
 

Show less