Electrochemistry Flashcards
Electrode
A system where a metal is in equilibrium with its ion.
Salt bridge
Completes the electric circuit making a liquid junction. It is a glass tube filled with an solution of an electrolyte such as KNO3.
Electrochemical cell
Consists of 2 electrodes in contact with an electrolyte.
Liquid junction potential
Potential generated due to the presence of 2 different electrolytes in the electrode compartment. Can be minimised if the electrodes are connected through a salt bridge.
Galvanic cell (voltaic cell)
Cell is able to produce electricity through a spontaneous reaction
Electrolytic cell
Cell is not able to produce electricity through a spontaneous reaction hence an external source of current is required.
Anode and Cathode
The electrode at which oxidation takes place is called the anode and the electrode at which reduction takes place is called the cathode.
Special point to remember regarding cell notations
Electrode corresponding to the oxidation half reaction in a cell is always written on the left hand side.
If there is a liquid junction potential present then a “ ⁞ ” is used between two
electrodes
Factors affecting electrode potential
temperature
concentration of the electrolyte
nature of the electrolyte
pressure of the gas
type of electrolyte
Electrolysis
Conducting a non-spontaneous reaction using electrical energy from outside is known as electrolysis.
When the cell emf is a negative value
Reaction is non-spontaneous hence in order to conduct this reaction external electric supply should be used of minimum voltage depicting the positive value of the negative value obtained.
Anode and cathode during electrolysis
Anode is the electrode connected to the positive terminal while the cathode is the electrode connected to the negative terminal
Who described electrolysis
Michael Faraday
Oxidation and reduction of water (reactions)
2H2O(l) → O2(g) + 4H+(aq) + 4e-
2H2O(l) + 2e →H2(g) + 2OH-(aq)
The charge required for a mole of an electron
96485 C mol-1
Approximately 96500 C mol-1
