procedure of adding water to the acid is generally avoided since the heat released may boil the solution, spraying droplets of hot acid during the process Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, and hydrogen, with the molecular formula H2SO4. It is a colorless, odorless, and viscous liquid that is miscible with water. Pure sulfuric acid does not occur naturally due to its strong affinity t "C… Directly dissolving SO3 in water, called the "wet sulfuric acid process", is rarely practiced because the reaction is extremely exothermic, resulting in a hot aerosol of sulfuric acid that requires condensation and separation. In the first step, sulfur is burned to produce sulfur dioxide: 2 CuSO4 + 2 H2O → 2 Cu + 2 H2SO4 + O2 More costly, dangerous, and troublesome is the electrobromine method, which employs a mixture of sulfur, water, and hydrobromic acid as the electrolyte. The sulfur is pushed to bottom of container under the acid solution. Then the copper cathode and platinum/graphite anode are used with… Also, because the acid is denser than water, it sinks to the bottom. Heat is generated at the interface between acid and water, which is at the bottom of the vessel. Acid will not boil, because of its higher boiling point. Warm water near the interface rises due to convection, which cools the interface, and prevents boiling of either acid or water. In contrast, addition of water to concentrated sulfuric acid results in a thin layer of water on top of the acid. Heat generated in this thin layer of water can boil, leading to the dispersal of a sulfuric acid aerosol, or worse, an explosion. Preparation of solutions greater than 6 M (35%) in concentration is dangerous, unless the acid is added slowly enough to allow the mixture sufficient time to cool. Otherwise, the heat produced may be sufficient to boil the mixture. Efficient mechanical stirring and external cooling (such as an ice bath) are essential. Reaction rates double for about every 10-degree Celsius increase in temperature. Therefore, the reaction will become more violent as dilution proceeds, unless the mixture is given time to cool. Adding acid to warm water will cause a violent reaction. On a laboratory scale, sulfuric acid can be diluted by pouring concentrated acid onto crushed ice made from de-ionized water. The ice melts in an endothermic process while diluting the acid. The amount of heat needed to melt the ice in this process is greater than the amount of heat evolved by diluting the acid so the solution remains cold. After all the ice has melted, further dilution can take place using water.