Electrochemistry

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Electrochemistry

Published by: Nuru

Published date: 25 Jun 2021

Electrochemistry Photo

Electrochemistry

The branch of physical chemistry which deals with the flow of electrons is called electrochemistry.

Metallic conduction: The conductors in which electricity moves without producing any chemical change are called Metallic conductors. And such conduction is known as metallic conduction.

Metallic conduction: The conductors which undergo chemical changes and conduct electricity either in the aqueous form or in the molten form are called electrolytic conductors. And such conduction is known as electronic conduction. They are also called electrolytes.

Electrolytic conductors are two types of electrolytes.

  1. Strong electrolytes:- The electrolytes which are almost completely ionized into their constituent ions when dissolved in water are called strong electrolytes. Eg:- HCL, H2SO4, KCL, NaCl, NaOH, etc.
  2. Weak electrolytes:- The electrolytes which are partly ionized when dissolved in water are called weak electrolytes. Eg – CH3COOH, NH4OH, Fe(OH)3, etc.

Arrhenius theory of ionization

Some fundamental postulates of Arrhenius's theory of ionization.

  1. When any electrolyte is dissolved in water, it splits up into electrically charged particles called ions. This process is known as ionization or dissociation. Positively charged particles are called cations while negatively charged particles are called anions.
  2. The total number of cations is always equal to the total number of anions in a solution. So the solution as a whole is electrically neutral.
  3. The electrical conductivity of the electrolyte in a solution is due to the migration of anions towards oppositely charged electrodes.
  4. The process of ionization is reversible. Ions are reuniting to give undissociated molecules and at the same time, undissociated molecules are ionizing. So, a dynamic equilibrium is established between ions and the undissociated molecules.
  5. The process of ionization is not completed. The extent of ionization is expressed in the degree of ionization which is denoted by ‘α’ Thus, the degree of ionization is defined as the fraction of a total number of moles of electrolyte which split into ions.

degree of ionization = no. of moles of electrolytes which split into ion / total no. of moles of electrolytes dissolved

  1. The electrical conductivity of the electrolyte, in the solution, is the number of ions produced by them.

Factors affecting the degree of ionization:-

Following are the factors:-

  • Nature of electrolytes- Degree of Ionization depends upon nature of electrolytes. Strong electrolytes have a high degree of ionization while weak electrolytes have a low degree of ionization.
  • Nature of solvent- The ionization power of solvent depends upon its dielectric constant. Greater the value of dielectric constant greater will be the ionizing power of the solvent and greater will be the degree of ionization
  • Dilution- The degree of ionization increase with the increase in dilution. At infinite dilution, even the weak electrolytes are almost completely ionized.
  • Temperature- Degree of ionization increases with increase in temperature.

Therefore the electrochemistry is explained above.