The dihydrogen is prepared by electrolysis of acidified water using platinum electrodes. generally acid is sulphuric acid and base is sodium hydroxide is used.
Role of electrolyte-
The electrical conductivity of pure water is very low due to the absence of ions in it. Hence electrolysis of water takes place at slow rate. If we add an electrolyte as an acid or base it will increase the rate of electrolysis. Electrolytes provide ions in this process for the better conduction of electricity.