CBSE Class 10 Answered

Electrolysis of water is the decomposition of water (H₂O) into oxygen (O₂) and hydrogen gas (H₂) due to an electric current being passed through the water. This electrolytic process is rarely used in industrial applications since hydrogen can be produced more affordably from fossil fuels.

An electrical power source is connected to two electrodes, or two plates, (typically made from some inert metal such as platinum or stainless steel) which are placed in the water. In a properly designed cell Hydrogen will appear at the cathode (the negatively charged electrode, where electrons are pumped into the water), and oxygen will appear at the anode (the positively charged electrode). The generated amount of hydrogen is twice the amount of oxygen, and both are proportional to the total electrical charge that was sent through the water. However, in many cells competing side reactions dominate, resulting in different products.

Hoffman voltameter connected to a direct current power supply.