Electrochemistry & Redox

Anode

The electrode at which oxidation occurs.

Dimensionless

Anodising

An electrolytic process that thickens the natural protective oxide layer on a metal, especially aluminium.

2Al + 3H₂O → Al₂O₃ + 6H⁺ + 6e⁻ μm

Electrochemistry & Redox

Calomel Electrode

A reference electrode based on the equilibrium between mercury, mercury(I) chloride and chloride ions.

Hg₂Cl₂ + 2e⁻ ⇌ 2Hg + 2Cl⁻ V

Electrochemistry & Redox

Cathode

The electrode at which reduction occurs.

Dimensionless

Electrochemistry & Redox

Cathodic Protection

The prevention of corrosion by forcing the metal to be protected to act as a cathode.

V

Electrochemistry & Redox

Cell Notation

A shorthand convention for representing an electrochemical cell using vertical lines for phase boundaries.

Zn(s) | Zn²⁺(aq) ‖ Cu²⁺(aq) | Cu(s) Dimensionless

Electrochemistry & Redox

Cell Potential

The difference in electrical potential between the two electrodes of an electrochemical cell.

E_cell = E_red(cathode) − E_red(anode) V

Electrochemistry & Redox

Concentration Cell

A galvanic cell in which both electrodes are identical and the potential arises solely from a difference in concentration.

E = (0.0592/n) log(C₂/C₁) V

Electrochemistry & Redox

Conductometric Titration

A titration in which the end point is found from changes in the conductivity of the solution.

S/m

Electrochemistry & Redox

Corrosion

The gradual destruction of a metal by electrochemical reaction with its environment.

mm/year

Electrochemistry & Redox

Daniell Cell

The classic galvanic cell consisting of a zinc electrode in zinc sulfate and a copper electrode in copper sulfate.

Zn + Cu²⁺ → Zn²⁺ + Cu, E° = 1.10 V V

Electrochemistry & Redox

Decomposition Potential

The minimum voltage that must be applied to an electrolytic cell before continuous electrolysis begins.

V

Electrochemistry & Redox

Dry Cell

A primary cell using a moist paste rather than a liquid electrolyte, so it can be used in any orientation.

Zn + 2MnO₂ + 2NH₄⁺ → Zn²⁺ + Mn₂O₃ + 2NH₃ + H₂O V

Electrochemistry & Redox

Electrochemical Cell

A device in which a redox reaction and an electric current are interconverted through two separated electrodes.

V

Electrochemistry & Redox

Electrochemical Equivalent

The mass of a substance liberated by the passage of one coulomb of charge.

Z = M / (nF) g/C

Electrochemistry & Redox

Electrochemical Series

A list of redox couples arranged in order of their standard electrode potentials.

V

Electrochemistry & Redox

Electrochemistry

The study of the relationship between chemical change and electrical energy.

V

Electrochemistry & Redox

Electrode

A conductor through which electric current enters or leaves an electrolyte.

Dimensionless

Electrochemistry & Redox

Electrolysis

The decomposition of an electrolyte by passing an electric current through it.

C

Electrochemistry & Redox

Electrolyte

A substance that produces mobile ions when dissolved or molten and therefore conducts electricity.

S/m

Electrochemistry & Redox

Electrolytic Cell

An electrochemical cell in which an external electrical supply drives a non-spontaneous redox reaction.

E°cell < 0 V

Electrochemistry & Redox

Electrolytic Conductivity

The ability of an electrolyte solution to conduct electric current, equal to the reciprocal of its resistivity.

κ = (1/R)(l/A) S/m

Electrochemistry & Redox

Electromotive Force

The maximum potential difference a cell can produce, measured when no current is being drawn.

emf = E_cathode − E_anode V

Electrochemistry & Redox

Electroplating

The deposition of a thin metal coating onto a conducting surface by electrolysis.

g