Part and weak acids, 2: 1. Graph your data for the titration of acetic acid and
ID: 503607 • Letter: P
Question
Part and weak acids, 2: 1. Graph your data for the titration of acetic acid and sodium hydroxide. 2. The midpoint of the steepest increase in pH isthe equivalence use the equivalence point on your graph to estimate pKa and Ka for acetic acid. 3. Buffer capacity has a rather loose definition, yet it is an important property of buffers. A commonly use definition is "the amount of H+ oroH-that can be neutralized before the pH changes to a significant degree." Use your data to determine the buffer capacity of your pH 4 buffer. Part 3: 1. Use your data to determine the buffer capacity of your pH 10 buffer. Conclusion & Post-lab Questions 1. Explain why the ammonium chloride and sodium acetate solutions were not neutral. write chemical reaction equations to support your explanation 2. write reaction equations to explain how your acetic acid-sodium acetate buffer reacts with an acid and reacts with a base. 1. Based on your results from part 2, how consistent is you Ka value? How accurate is it? 2. What effect does a buffer solution have on the ph of a solution by addition of a strong acid? A strong base? Explain your reasoning.Explanation / Answer
Solution :-
Q1 Ammonium chloride is the conjugate acid of the NH3 and sodium acetate is the conjugate base of the acetic acid.
A salt of strong acid and weak base gives the acidic solution
A salt of strong base and weak acid gives the basic solution
Following are the reaction equations
Reaction of the ammonium chloride in water
NH4Cl + H2O ------ > H3O+ + NH3 + Cl^-
It produces the H3O+ therefore the ammonium chloride is salt is acidic.
Reaction of sodium acetate in water
CH3COONa + H2O ------ > CH3COOH + OH- + Na^+
It produces the OH- therefore sodium acetate is basic in nature.
Q2 Reactions of the acetic acid and sodium acetate with addition of acid and base
Reaction when the acid is added
CH3COO^- + H^+ ---- > CH3COOH
Reaction when the base is added
CH3COOH + OH^- ----- > CH3COO^- + H2O
Q3) To find the consistency of the Ka value we need the calculated Ka value
Q4) A buffer solution is the solution which resist the sudden change in the pH when strong acid or base is added to the buffer solution because conjugate base of the buffer reacts with acid to neutralize it
When strong acid is added then pH slowly decreases and when base is added then pH is slowly increases, because acid from the buffer solution reacts with added base to neutralize it.