Why does combining Hydrogen, Oxygen and Sulphur produce a liquid?

[BenDover]

TL;DR Summary

Crazy result

Hydrogen is a gas, sulfur is a solid, oxygen is a gas, why does combining them to produce sulfuric acid produce a liquid?

 

[Ygggdrasil]

Chemical reactions create new substances with new properties. The properties of the products of a chemical reaction are not necessarily the same as the reactants that produce them.

 

[chemisttree]

Actually, when you combine these they produce a gas. When you combine the gas with water you get what is commonly known as sulfuric acid. Same goes for hydrochloric acid.

 

[Hillbillychemist]

As chemistree stated when you burn sulfur with oxygen you first get SO2 then SO3 both of which are gases. SO3 then combines with water, H2O, to form sulfuric acid, H2SO4, a liquid. The forces that hold molecules together are electrostatic. All molecules have temporary dipoles due to the movement of electrons within the molecules. The attraction due to these temporary dipoles is called the Vander Walls force. The larger the molecule the larger the combined attractions (van der Walls force) between the molecules. Additionally, some molecules like sulfuric acid are non-symmetrical meaning that there is an unbalanced distribution of electrons within the molecule. This produces a permanent dipole and as a result, stronger attraction between the molecules. The attraction between molecules is what determines whether you have a gas, a liquid, or a solid. The stronger the forces the higher the melting point and the boiling point.

 

[sysprog]

Anaerobic breakdown of organic compounds produces 'swamp gas', i.e. hydrogen sulfide, H2S, which is highly flammable, and when combusted it produces H2SO4.

 

[snorkack]

Actually, when you combine these they produce a gas. When you combine the gas with water you get what is commonly known as sulfuric acid. Same goes for hydrochloric acid.

Wrong for sulphuric acid.
At 1 bar partial pressure, SO₂ is indeed a gas - condenses at -10 Celsius.
However, SO₃ is NOT a gas at 1 bar and 20 Celsius. It easily condenses to a liquid, boiling point +45 Celsius, and less easily to a solid that sublimes at IIRC 62 Celsius.

Note that reaction of hydrogen - a gas, condenses at -253 Celsius - and oxygen - a gas, condenses at -183 Celsius - gives water - a liquid, condenses at +100 Celsius.

 

[chemisttree]

Wrong for sulphuric acid.
At 1 bar partial pressure, SO₂ is indeed a gas - condenses at -10 Celsius.
However, SO₃ is NOT a gas at 1 bar and 20 Celsius. It easily condenses to a liquid, boiling point +45 Celsius, and less easily to a solid that sublimes at IIRC 62 Celsius.

Note that reaction of hydrogen - a gas, condenses at -253 Celsius - and oxygen - a gas, condenses at -183 Celsius - gives water - a liquid, condenses at +100 Celsius.

Wrong for SO3. The reaction to produce SO3 occurs at hundreds of degrees C over catalysts and produces a gas at that temperature.