Answer to Question #184311 in General Chemistry for feag

Question

A solution is prepared by mixing equal volumes of 0.20M HC₂H₃O₂ and 0.40M NaC₂H₃O₂. Which of the following correctly describes what occurs if a small amount of HCl (aq) or NaOH (aq) is added? Explain

• If NaOH (aq) is added, the pH will increase only slightly because the OH⁻ ions will react with HC₂H₃O₂ molecules.
• If HCl (aq) is added, the pH will decrease only slightly because the H⁺ ions will react with HC₂H₃O₂ molecules.

• If HCl (aq) is added, the pH will increase only slightly because the Cl, −, ions will react with C, 2, H, 3, O, 2, −, ions.
• If NaOH (aq) is added, the pH will decrease only slightly because the OH⁻ ions will react with C₂H₃O₂⁻ ions.

Answer 1

• If HCl (aq) is added, the pH will decrease only slightly because the H⁺ ions will react with HC₂H₃O₂ molecules.

The difference lies in there ionization. Hydrochloric acid is a strong acid which means it gets completely ionized into H⁺ & Cl^- which in turn, means that all the H⁺ present in HCl will be present in solution now. But in case of acetic acid it is not so. As it is a weak acid it don't get ionized completely.