Worksheet Chapter 1: Redox Equilibrium

1. Write the ionic half-equation for the oxidation of iron(II) ions, Fe²⁺, to iron(III) ions, Fe³⁺.

2. Chlorine water is added to a test tube containing potassium iodide solution, KI, followed by 2 cm³ of 1,1,1-trichloroethane. Describe the color observation in the organic layer and write the ionic equation for the reaction.

3. True or False: In an electrolytic cell, electrical energy is converted into chemical energy.

4. True or False: A species with a more negative standard electrode potential (E°) value is a stronger reducing agent.

5. Fill in the blank: The loss of electrons in a chemical process is termed as ________.

6. Iron(III) oxide (Fe₂O₃) is reduced to molten iron in a blast furnace using carbon monoxide (CO). Write the balanced chemical equation, state the change in oxidation number of iron, and identify the reducing agent.

7. Explain briefly why galvanising iron with zinc prevents iron from rusting, even when the zinc coating is scratched.

8. In the electrolysis of molten lead(II) bromide, PbBr₂, using carbon electrodes, what product is formed at the cathode?

9. A simple chemical cell is constructed using Zinc (Zn) and Copper (Cu) dipped in their respective sulfate solutions. Given E°(Zn²⁺/Zn) = -0.76 V and E°(Cu²⁺/Cu) = +0.34 V, state which metal acts as the negative terminal and calculate the overall standard cell potential (E°cell).

10. Calculate the oxidation number of sulfur in the thiosulfate ion (S₂O₃²⁻).