QS Study

Comparison of metallic conduction and electrolytic conduction

Conductors of electricity may be divided into two groups according to the mechanism by which electricity is carried through them. In a metallic conductor, the charge carriers are electrons and, under the influence of an external electric field, they acquire some average drift velocity in the direction opposite the field.

Metallic conduction

  • The current is solely carried by the electrons in the conduction band.
  • The velocity of the electrons is very large.
  • During passage of current no chemical reaction occurs; only heating effect is produced.
  • Specific conductance of many metals are quite high, they are very good conductors of electricity.
  • Temperature co-efficient in general is negative (alloys show complex behavior).
  • Ohm’s law applies.
  • Conductance may be measured by d-c or a-c current.

Electrolytic conduction

  • The current is carried by both cations and anions.
  • Ionic velocities are much smaller than electron velocities.
  • Passage of current brings about chemical reactions; heat is also evolved.
  • Specific conductance is low; they are moderately good conductors.
  • Temperature co-efficient is positive.
  • Ohm’s law applies
  • Conductance is measured by a-c source; d-c current can be used only by elaborate arrangements.