Chemistry ch 10 electrode potential

definition

the potential setup when an electrode is in contact with one molar solution of its own ions at 298 K is known as standard electrode potential. It is represented as E not.

explanation

whenever a metal rod or strip is dipped into a solution of its own ions, there are two possibilities

metal atoms may get dissolved as positive ions. electrons are deposited on the electrode. in this way, electrode carries negative charge and solution carries positive charge.

metal ions in the solution may get electrons from the metal strip or rod and get discharged as atoms. in this way, electrode carries positive charge while negative charge accumulates in the solution.

explanation of electrode potential in terms of equilibrium between metal atoms and ions

the electrode potential setup can be explained in terms of equilibrium between metal atom and its own ions.

same two reaction points as earlier explanation

whichever tendency is greater determines the reduction or oxidation potentials of the element. eventually a stage reaches when the two opposing processes proceed at equal rates and then there will be no further change in the potential difference between metal and its ions.

example

when zinc rod is placed in a solution f it s own ions, then zinc rod will bear an accumulation of negative charges. this is due to greater tendency of zn to lose electrons. the negative charge on zn rod will attract an atmosphere of positively charged zinc ions around the rod to form an electrical double layer.

electrochemical series

the list in which elements are arranged in order of their standard electrode potential(standard reduction potential) on hydrogen scale is called electrochemical series.

will affect values of reduction potential

change in

temperature

concentration

pressure