The hydrogen gas, which is just liberated as a result of a chemical is called nascent hydrogen or newly born hydrogen. It is obtained by passing dihydrogen gas at atmospheric pressure through an electric arc between two tungsten rods.
The electric arc maintains a temperature around 4000 – 4500°C. As the molecules of dihydrogen gas pass through the electric arc, these absorb energy and get dissociated into atoms as nascent hydrogen. It is more reactive than ordinary hydrogen and its colour is not discharged. (pink in colour).