To study the electrolysis of water
Electrolysis and composition of water
Electrolysis is the chemical process of using electric current to decompose a substance into an electrolyte. An electrolyte is a substance, usually an iconic compound, that conducts electricity. Water, a molecular compound comprising oxygen and hydrogen in a 2:1 ratio, is represented by the chemical formula H₂O.
What is the electrolysis of water?
The DC produced by an electrolyte consisting of hydrogen and oxygen is directly proportional to the electrical charge in the solution. The cathode contains hydrogen electrolytes, while the anode has oxygen electrolytes.
When an electrical power source is connected to metal plates made of platinum or iridium and an electrical current is passed through the solution, the ionic compounds are broken down into simpler substances. Hydrogen is generated at the cathode side, while oxygen is produced at the anode side. The chemical reaction of gas decomposition occurs by transferring electric current through the solution. Fig.1 Process of electrolysis of water
Both oxygen and hydrogen gas produced air bubbles at the places of the anode and cathode, where the anode observes the positive ions (oxygen), and the cathode observes the negative ions (hydrogen).
Capturing gases released from the electrodes
Electrolysis of water by the addition of salts
Equations of electrolysis of water (neutral pH)
The connection between water electrolysis and Faraday’s First Law of electrolysis
The electrolysis process of water relates to the first law of electrolysis coined by Michael Faraday. The law states that the amount of reaction at any electrode during electrolysis by a current is directly proportional to the quantity of electric current passed through the electrolyte.
Here, m represents the mass of the electrolyte.
Q represents the charge of the electrolyte.
Role of electrocatalysts
Electrocatalysts are non-consumable compounds that enhance the electrochemical processes. The water electrolysis cell’s operating circumstances dictate the design of the catalysts.
For example, the inert platinum electrode can be enhanced as a catalyst through:
Role of an electrolytic cell (Electrolyzers)
Fig.2 Structure of an electrolytic cell
An electrolytic cell is a device which is mainly used in the process of electrolysis. It has positive and negative charges that help to store positive and negative electrolytes in the cathode and anode during the process.
Three types of electrolyzers are being used, depending on the transport of electrolytes.
|Polymer Electrolyte Membrane (PEM) electrolyzer
|Separates polymer electrodes, facilitating hydrogen ion formation during oxidation, subsequently passing hydrogen to the cathode as a gaseous material.
|A dilute aqueous solution of sodium (or potassium) hydroxide is used to transport hydroxide ions to the anode, forming oxygen.
|Solid oxide electrolyzer
|It employs ceramic oxide to segregate electrodes, wherein water undergoes reduction into hydrogen and oxide ions at the cathode, and the generated oxide ions are transported to the anode, ultimately stored as gaseous oxygen.
Factors affecting the efficiency of electrolysis
Applications of electrolysis of water
Difference between Electrolytes and nonelectrolytes
Electrolytes are chemical substances that may dissolve in water and generate ions, facilitating electricity transmission through the solution.
Nonelectrolytes are chemical substances that do not conduct electricity when dissolved in water.
Electrolytes may be ionized when dissolved in water. Thus, electricity is transmitted through the solution.
Nonelectrolytes may not be ionised when dissolved in water.
Students will learn and understand: