the substance which deposited on cathode by electrolysis of liquid and
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Definition: electrolysis is the passage of a direct electric current through an ion-containing solution (for us, water and electrolyte). Electrolysis produces chemical changes at the electrodes.
When an electric current passes across a solid conductor, a magnetic field is created around the conductor and the conductor is heated by the passage of the current. Both the magnetic field and the heat bear a definite relationship to the magnitude of the current passing; the stronger the current the stronger the magnetic field; the stronger the current the more heat. Some liquids are conductors of electricity; mercury for one. The passage of a current through such a conductor produces identical results with those produced in solid conductors. Other liquids are also conductors, but besides passing of current creating a magnetic field and a heating effect, a portion of the liquid is split into two parts which may each be a chemical element, or one, or either may be a chemical group.

In the image above, two platinum plates are placed as shown, one plate is connected to the positive pole of the battery and the other to the negative. If a strong aqueous solution of hydrochloric acid is added, decomposition of the liquid will take place: hydrogen will be given off at the negative plate or cathode, and chlorine at the positive or anode. If the solution of hydrochloric acid is replaced by one of caustic soda, the caustic soda is split up by the current into oxygen, which is liberated at the anode, positive, and metallic sodium which is deposited on the cathode; but since metallic sodium cannot exist in contact with water, the following reaction takes place at the cathode: 2Na + 2 H 2O = 2NaOH + H2 Thus, by a secondary reaction, hydrogen is liberated at the cathode, or, in other words, water is split into its constituents, while the caustic soda is reformed.
Now, let the caustic soda solution be replaced by an aqueous solution of sulphuric acid. In this case hydrogen will be liberated at the cathode and the group SO4 at the anode, but the group SO4 cannot exist in contact with water, as the following reaction takes place: 2SO4 + 2H2O = 2H2SO4 + O2 Thus by a secondary reaction, oxygen is liberated at the anode, or, in other words, water is split into its constituents while the sulphuric acid is reformed.
Liquids which, under the influence of the electric current, behave in the manner of the above are termed "Electrolytes",
The laws relating to this decomposition of liquids by the electric current were enunciated by Faraday as follows:
The quantity of an electrolyte decomposed is proportional to the quantity of electricity which passes.
The mass of any substance liberated by a given quantity of electricity is proportional to the chemical equivalent weight of the substance.
By the chemical equivalent weight of a substance is meant, in the case of elements, the figure which is obtained by dividing its atomic weight by its valency, which in the case of compounds, it is the molecular weight divided by the valency of the compound. However, many elements have more than one valency, therefore they have more than one chemical equivalent weight.
When an electric current passes across a solid conductor, a magnetic field is created around the conductor and the conductor is heated by the passage of the current. Both the magnetic field and the heat bear a definite relationship to the magnitude of the current passing; the stronger the current the stronger the magnetic field; the stronger the current the more heat. Some liquids are conductors of electricity; mercury for one. The passage of a current through such a conductor produces identical results with those produced in solid conductors. Other liquids are also conductors, but besides passing of current creating a magnetic field and a heating effect, a portion of the liquid is split into two parts which may each be a chemical element, or one, or either may be a chemical group.

In the image above, two platinum plates are placed as shown, one plate is connected to the positive pole of the battery and the other to the negative. If a strong aqueous solution of hydrochloric acid is added, decomposition of the liquid will take place: hydrogen will be given off at the negative plate or cathode, and chlorine at the positive or anode. If the solution of hydrochloric acid is replaced by one of caustic soda, the caustic soda is split up by the current into oxygen, which is liberated at the anode, positive, and metallic sodium which is deposited on the cathode; but since metallic sodium cannot exist in contact with water, the following reaction takes place at the cathode: 2Na + 2 H 2O = 2NaOH + H2 Thus, by a secondary reaction, hydrogen is liberated at the cathode, or, in other words, water is split into its constituents, while the caustic soda is reformed.
Now, let the caustic soda solution be replaced by an aqueous solution of sulphuric acid. In this case hydrogen will be liberated at the cathode and the group SO4 at the anode, but the group SO4 cannot exist in contact with water, as the following reaction takes place: 2SO4 + 2H2O = 2H2SO4 + O2 Thus by a secondary reaction, oxygen is liberated at the anode, or, in other words, water is split into its constituents while the sulphuric acid is reformed.
Liquids which, under the influence of the electric current, behave in the manner of the above are termed "Electrolytes",
The laws relating to this decomposition of liquids by the electric current were enunciated by Faraday as follows:
The quantity of an electrolyte decomposed is proportional to the quantity of electricity which passes.
The mass of any substance liberated by a given quantity of electricity is proportional to the chemical equivalent weight of the substance.
By the chemical equivalent weight of a substance is meant, in the case of elements, the figure which is obtained by dividing its atomic weight by its valency, which in the case of compounds, it is the molecular weight divided by the valency of the compound. However, many elements have more than one valency, therefore they have more than one chemical equivalent weight.
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these are the substance which have to be electroplated
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