Physical Properties Of Hydrogen

Physical Properties of Hydrogen

What Is Hydrogen?

Hydrogen is the lightest and most abundant chemical element in the universe. Hydrogen is the largest element in the periodic table and most plentiful in the universe.

Hydrogen (H₂) gas is a colorless, odorless, and tasteless non-metallic and extremely flammable gas.

Hydrogen gas is undetectable by human senses.

Hydrogen comes Greek words hydro and genes. Hydrogen was discovered by Antoine Lavoisier.

The sun generates energy by the nuclear fusion of hydrogen atoms into helium. Hydrogen gas is an extremely flammable and explosive gas.

Physical Properties of Hydrogen

Hydrogen synonym	Dihydrogen, Protium, Deuterium,  tritium
Atomic symbol	H
Atomic number	1
Atomic Mass	1.008 u
Molecular weight	2.016 gm/mol
Physical state	Gaseous form (at room temperature)
Colour	Colorless
Odor	Odorless
Density	0.08988 g/L (at 0°C and 1 atm pressure)
Boiling point	-252.87°C
Melting point	-259.2°C
Autoignition temperature	500 to 571°C (932 to 1059.8°F)
Flashpoint	Not available
Lower Explosive Limit	4%
Upper Explosive limit	76%
Specific volume (ft3/lb)	12.0482
PH	Not available
Vapor density	0.0696 (relative to air = 1)
Heat of combustion	286 KJ/mol

Expand Your Knowledge on [P^H definition, uses]

Why does hydrogen have no flash point?

Flashpoint typically applies to liquids, indicating the lowest temperature at which they emit enough vapor to ignite. Hydrogen is already a gaseous form at room temperature.

Chemical Properties of Hydrogen

1. Flammable
   • Hydrogen is highly flammable and burns readily in air or oxygen.
   • Hydrogen combustion reactions produce water and heat.
   • The hydrogen flame is invisible, and the odor is undetectable and testless.
     
2. Hydrogen react with metals
   • Hydrogen gas reacts with metals to form metal hydrides.
     • Hydrogen reacts with sodium metal to form sodium hydride.
       2Na+H₂​→2NaH
     • Lithium reacts with hydrogen to form lithium hydride.
       2Li+H₂ →2LiH
       
3. Hydrogen with Halogen
   • Hydrogen reacts with halogen to produce hydrogen halides.
   • H₂​_(g) +X₂​_(g) →2_(liq)
     • Hydrogen reacts with chlorine to produce hydrochloric acid.
       H₂​+Cl₂​ →2HCl
     • Hydrogen reacts with fluorine to produce hydrofluoric acid.
       H₂​+F₂→ 2HF
       
4. Hydrogen reaction with Oxygen
   • Hydrogen reacts with oxygen to form water. This reaction is a highly exothermic reaction and releases a large amount of energy.
     2H_2(g) + O_2(g) → 2H₂O_(l) + Heat
     
5. Ammonia Synthesis (Haber process)
   • Hydrogen and nitrogen react between Fe catalyst under pressure and high temperature.
     N_2​(g)+3H_2​(g) → 2NH3​_(g)

Uses of Hydrogen

• Used extensively in the manufacture of ammonia (NH₃) for fertilizers, explosives, and cleaning agents.
• Converts liquid vegetable oils to solid fats (e.g., margarine).
• Used in hydrocracking and desulfurization to refine crude oil and remove impurities like sulfur.
• Reacts with carbon monoxide to form methanol (CH₃OH).
• Liquid hydrogen combined with liquid oxygen is used as a high-efficiency propellant in space rockets.
• chemical syntheses and as a reducing gas in analytical and research labs.
• Deuterium and tritium are isotopes of hydrogen used in nuclear research and tracing.

Q&A

1. What is the formula of hydrogen gas?
   Ans. Hydrogen (H₂) gas is colorless, odorless, and tasteless, meaning it’s undetectable by human senses. The sun generates energy by the nuclear fusion of hydrogen atoms into helium. Hydrogen gas is an extremely flammable and explosive gas.
   
2. Where is hydrogen used?
   Ans. Hydrogen gas is used in the manufacture of ammonia and methanol, research labs, and as propellant in space rockets.
   
3. What is the smell of hydrogen?
   Ans. Hydrogen gas is an odorless gas.