Question

1. Potassium permanganate (KMnO₄ ) is a commonly used oxidant in many redox titrations. In one such titration, KMnO₄ solution in a buret is added to a solution of oxalic acid in the Erlenmeyer flask.

2MnO₄⁻(aq) + 5H₂C₂O₄(aq) + 6H⁺(aq) → 2Mn²⁺(aq) + 10 CO₂(g) + 8 H₂O(l)

Every component except permanganate (purple) is colorless. The end point of the reaction will be signaled by:

a. The first appearance of the purple color in the solution being titrated

b. The disappearance of the purple color in the solution being titrated

c. The disappearance of the purple color of the permanganate in the buret

d. The first appearance of a green color in the permanganate solution in

2. Assuming 25 ^oC, a basic solution has a:

a. pH less than 7.00

b. [H₃O⁺ ] greater than 1.00 × 10⁻⁷ M

c. [H₃O⁺ ] greater than [OH ⁻ ]

d. [OH ⁻ ] greater than 1.00 × 10⁻⁷ M

e. pH equal to 7.00

3. Consider the following reaction at 25 °C;

Cu²⁺ (aq) + Fe (s) → Cu (s) + Fe²⁺ (aq); E⁰_cell = 0.78 V (25 °C)

What would be the value of E_cell at 25 °C, if [Fe²⁺] = 0.40 M and [Cu²⁺] = 0.040 M.