Electrolysis is a branch studied by Electrochemistry, in which electric energy is transformed into chemical energy, i.e., it is a process that is the opposite of what occurs in batteries. The process of the batteries is spontaneous, but the process of electrolysis is not, because it is necessary to supply the electric current through some generator, which may even be a battery or battery, for an oxidation reaction to happen. The use of graphite anode is very important here.
All electrolysis needs the direct current generator that will pass the electric current through an ionic liquid, which is called an electrolyte. In the electrolyte are immersed two electrodes, which are generally inert, made of platinum or graphite, one being the cathode (negative pole) and the other is the anode (positive pole). The container where the electrolyte is located and the electrodes immersed in it, as well as where the whole oxi-reduction process takes place, are called the electrolyte vat.
Electrolytic tank and other electrolysis parts
The electrolysis then proceeds as follows: when the generator is started, the electrons are transported from the generator by its negative pole in the case of the battery, the negative pole is the anode and enter the electrolyte bowl through the cathode negative pole, in the case of electrolysis, where a reduction reaction takes place, where the electrons are received, as shown by the generic semi-reaction below:
Cathode (negative pole): Reduction: C x + + x and – → C
Then, in the electrolytic tank, the electrons emerge from the anode positive pole in electrolysis, where oxidation occurs, i.e. the loss of electrons, and reach the generator by its positive pole cathode. The oxidation semi-reaction that occurs at the anode of the electrolytic cell is given below:
Anode (positive pole): Oxidation: A y- → A + ye –
The overall reaction is given by the sum of these two semi-reactions. Thus, the energy that was used to discharge the ions at the end of the reaction produces simple or metallic substances widely used in industries. Such energy is the electrical energy that is stored in these substances in the form of chemical energy.
Depending on the type of electrolyte, electrolysis can be classified in two ways:
Fire electrolysis: Electrolyte is a fused substance, i.e. it is in a liquid state without the presence of water, because the melting point of molten materials is usually very high.
For example, electrolysis of molten cooking salt produces two very important substances not found in isolation in nature: metallic sodium and chlorine gas. The melting point of the salt is greater than 800.4 ° C, so there is certainly no water in the medium, given that the melting point of water is 0 ° C and the boiling point is 100 ° C. from the sea.
Scheme of electrolysis of fused sodium chloride
Electrolysis in aqueous medium: In this case, the electrolyte is an aqueous solution with dissolved ions. In aqueous electrolysis, there are, besides the dissolved substance ions, the water ions (H + and OH – ). Thus, you need to refer to the ease of discharge lists to know which anion will be and which cation will participate in the oxeduction reactions and become neutral.