What is Electrode in Chemistry?
Electrode, the electronic conductor, usually metals partly immersed in an electrolytic solution and imparts or receives electrons from the medium in a storage battery, solid, gas, or vacuum and uses commonly in electrochemical cells, semiconductors like diodes, and different types of medical devices. In the electrolysis of electrochemical cells, the electrical energy from the external sources is used to perform a chemical change or redox reaction. The negative electrode where oxidation occurs is called the anode and the positive electrode where reduction occurs is called the cathode in chemistry or chemical science.
Current carrying ions are discharged at the electrode of the chemical solution. In water solution, when negative ions are difficult to be discharged due to high deposition potential and hydroxyl ion gets deposited. When positive ions are difficult to be discharged, hydrogen ions are discharged from the solution. According to the reactivity, the electrode is two types, inert electrodes, reacting electrodes.
These electrodes do not participate in the electrolysis reaction but help to transfer electrons from cathode to anode. Platinum (Pt) and gold are examples of such types of electrodes. When copper sulfate (CuSO4) electrolyzed between the platinum electrode, metallic copper is deposited at the cathode by receiving two electrons and hydroxyl ion (OH–) deposited at the anode. Due to high deposition potential, sulfate ions (SO4-2) will not be discharged at the anode.
These electrodes participate in the electrolysis reactions either by contributing ions to the solution or accepting the discharged ions from the solution. When copper sulfate solution is electrolyzed between two copper electrodes, copper is deposited at the cathode as usual but equivalent copper is dissolved. The anode and the process are used for the purification of pure copper from its impure form.
Electrochemical cells are the device which generating electrical energy from the chemical reaction of the cell or using electrical energy to perform the chemical reaction. The electrochemical cell is mainly two types like the primary cell and the secondary cell. A primary cell is a device where electrode like cathode and anode is fixed and the cell reaction cannot be reversed. A secondary cell-like rechargeable battery is a chemical cell where chemical reactions are reversible. When the cell is charged, the anode becomes positive and the cathode becomes positive, and when discharged its works like a primary cell where the anode is negative and the cathode is the positive electrode. The lithium-ion batteries are examples of the secondary rechargeable chemical cell.
Uses of Electrode
Different type of electrode like gold, platinum, amorphous copper, silver used to define electrical conductivity in learning chemistry, a glass electrode is used for measurement of the pH of the solution, Batteries are the device contain a variety of electrode depending on the types. For example, lead-acid batteries contain lead electrodes, zinc-carbon batteries contain zinc and carbon electrodes, lithium polymer batteries contain solid lithium polymer electrodes. The electrode is also used in welding, membrane cathode and ECG, ECT, EEG, and defibrillator in biochemical research.