Assignment

1. Which English chemist is associated with the discovery of sodium and potassium in 1807, using a new method of electrolysis?
   • Joseph Priestley
   • Thomas Dalton
   • Humphrey Davy
   • Michael Faraday
2. What is the relationship between current and current density?
3. What is current density?
4. For a reaction at 298 K in which n = 1, a = 0.5, i₀ = 2.0×10⁻⁶ A and mass transfer effects can be ignored, calculate the current flowing at overpotentials of 30 mV and 150 mV using:
   1. the Butler–Volmer equation
   2. the Tafel equation
   With reference to your answers, comment on the validity of the Tafel equation.
5. The data tabulated below was obtained for the couple Ce⁴⁺/Ce³⁺ at a 0.5 cm² Pt electrode at 298 K. Assuming mass transfer effects can be ignored, determine the exchange current density and the transfer coefficient for the reaction.