Hydrogen gas is a colorless, odorless, and tasteless gas that is the lightest and most abundant element in the universe. It is represented by the chemical symbol H and has an atomic number of 1. Hydrogen gas is highly flammable and can form explosive mixtures with air, making it important to handle with care. In nature, hydrogen is often found combined with other elements, such as in water (H₂O) and organic compounds. It can be produced through various methods, including electrolysis of water and natural gas reforming. Hydrogen gas is increasingly being explored as a clean energy source for fuel cells and vehicles.