The credit for discovering hydrogen goes to T. Von Hohenheim, who accidently discovered the gas (H2) in the 15th century AD, when he mixed acids and metals. He was not sure if the mixing would produce a new chemical element. Next it was Robert Boyle who described the reaction between the two in 1671. It was Henry Cavendish who discovered it as a separate substance. He found that the reaction between acid and metal produced a gas which was highly inflammable. Later he also found that it turned to water when burnt. The experiments were repeated by Antonie Lavoisier in 1783, who named it Hydrogen.