Electrochemistry

Electrochemistry is the branch of chemistry which deals with the study of production of electricity from energy released during spontaneous chemical reactions and the use of electrical energy to bring about non-spontaneous chemical transformations.

Importance of electrochemistry

1. Production of metals like Na, Mg, Ca and Al.

2. Electroplating.

3. Purification of metals.

4. Batteries and cells used in various instruments.

Conductors

Substances that allow electric current to pass through them are known as conductors.

Metallic Conduction	Electrolytic Conduction
Electric current flows by movement of electrons.	Electric current flows by movement of ions.
No chemical change occurs.	Ions are oxidized or reduced at the electrodes.
It does not involve the transfer of any matter.	It involves transfer of matter in the form of ions.
Ohm's law is followed.	Ohm's low is followed.
Resistance increases with increase of temperature.	Resistance decreases with increase of temperature.
Faraday law is not followed.	Faraday law is followed.

Metallic conductors or electronic conductors

Substances which allow the electric current to pass through them by the movement of electrons are called metallic conductors, e.g., metals.

Electrolytic conductors or electrolytes

Substances which allow the passage of electricity through their fused state or aqueous solution and undergo chemical decomposition, are called electrolytic conductors, e.g., aqueous solution of acids, bases and salts.

Electrolytes are of two types -

Strong electrolytes

The electrolytes that completely dissociate or ionise into ions are called strong electrolytes. e.g., HCl, NaOH, K₂SO₄.

Weak electrolytes

The electrolytes that dissociate partially (α < 1) are called weak electrolytes, e.g., CH₃COOH, H₂CO₃, NH₄OH, H₂S, etc.