Like all elements and chemical compounds, sulfuric acid can exist as a solid, liquid, or gas. Boiling sulfuric acid heats the acid enough for it to become a gas. If this gas is not kept at a temperature above 639 degrees Fahrenheit (337 degrees Celsius), the molecules of sulfuric acid will condense again into a liquid. Humans and other life forms who come into contact with boiling sulfuric acid or the vapor created in the boiling process can be seriously injured.
The main effect of boiling sulfuric acid is that the acid undergoes a phase shift, in which it changes from a liquid into a gas. All chemicals can be transformed into a solid, liquid, or gaseous phase by changing the temperature of the substance or the pressure at which it is kept. At normal atmospheric pressure and room temperature, sulfuric acid is a liquid. When it is heated to its boiling point, the molecules are forced to move more rapidly than they do at cooler temperatures, creating more space between them, allowing the liquid sulfuric acid to transform into gaseous sulfuric acid.
In some cases, dilutions of sulfuric acid can be boiled at a temperature of 212 degrees Fahrenheit (100 degrees Celsius). This is the temperature at which water boils. Though sulfuric acid reacts readily with water, it is also commonly diluted with water. Heating sulfuric acid to 212 degrees Fahrenheit (100 degrees Celsius) allows the water in the dilution to change from a liquid into water vapor. It is then able to rise out of the sulfuric acid dilution, the effect of which is to create a higher concentration of sulfuric acid.
Boiling sulfuric acid will also have an effect on the environment around it. If boiling sulfuric acid comes into contact with human skin, it can cause both thermal and chemical burns. People who need to boil this type of acid must be extremely cautious as the effects of contact with boiling sulfuric acid can lead to serious injury or death. The acid can also eat away at or cause fires in objects it comes into contact with.
Like liquid sulfuric acid, gaseous sulfuric acid is highly corrosive and readily reacts with water, making it extremely dangerous and difficult to work with. Scientists who work with this chemical usually work with it in liquid form because it is easier to manage and because it is naturally a liquid at room temperature. It is easy, however, to accidentally bring this substance to a boil. When it is combined with water in order to dilute it, the chemical reaction that occurs generates a great deal of heat, sometimes enough to cause the sulfuric acid to boil. If this happens, people in the vicinity need to vacate the area until it is aired out so that they do not suffer chemical burns on their eyes or skin or damage to the cells in the mouth, nose, throat, or lungs due to inhalation of gaseous sulfuric acid.