Answer: Definitions of corrosion, electrode potential, electrochemical cell, wavelength and electroplating are given below.
a) Corrosion: Destruction or deterioration of a metal, starting at its surface, by chemical or electrochemical reaction with its environment is called corrosion. Example: rusting of iron.
b) Electrode potential: When a metal electrode is dipped in a solution of its own ions, a potential difference develops at the interface between the metal and the solution because of the tendency of the metal to lose or gain electrons. This potential difference is called the electrode potential. When measured at 25 °C with 1 M ion concentration (and 1 atm for gases) it is called the standard electrode potential, E°.
c) Electrochemical cell: A device consisting of two electrodes (electronic conductors such as metals or graphite) dipping in an electrolyte, in which oxidation occurs at one electrode (anode) and reduction at the other (cathode). If it converts chemical energy into electrical energy by a spontaneous redox reaction it is a galvanic (voltaic) cell, e.g. Daniell cell; if it uses electrical energy to drive a non-spontaneous reaction it is an electrolytic cell.
d) Wavelength: The distance between two successive crests (or two successive troughs) of a wave is called its wavelength. It is denoted by \(\lambda\) and is expressed in m, nm or Å. It is related to frequency by \(c=\nu\lambda\).
e) Electroplating: Electroplating is the process of depositing a thin, uniform, adherent coating of one metal on another metal (or conducting surface) by electrolysis. The article to be plated is made the cathode, the plating metal (or an inert electrode) is the anode, and a solution of a salt of the plating metal is the electrolyte; the current reduces the metal ions to metal on the article. It is done to prevent corrosion, improve appearance or increase hardness/wear resistance, e.g. nickel or chromium plating.