Sulfuric acid and potassium hydroxide are different in many ways. One is a liquid acid while the other is a solid base. Nonetheless, when they mix they form two useful compounds — water and potassium sulfate — which are also safer than their original constituents.
Two hydrogen atoms, one sulfur atom and four oxygen atoms comprise sulfuric acid, which is the most commonly produced chemical in the United States. It is a major part of many other chemical reactions. Sulfuric acid is extremely effective at pulling both itself and other chemicals apart to form new chemicals.
Potassium hydroxide, also known as caustic potash, typically comes in solid flakes and is made of one atom each of potassium, oxygen, and hydrogen. It has a tendency to absorb water and is frequently used in the production of soap. Other industrial uses include as an electrolyte in batteries, such as those in the Toyota Prius, and as an ingredient in the manufacture of biodiesel fuels.
The chemical reaction of sulfuric acid and potassium hydroxide is referred to as an acid-base neutralization. In these types of reactions, the acid and base mix together to form water and a salt, although not necessarily table salt. Sulfuric acid and potassium hydroxide produce the salt, potassium sulfate. To be more specific, two molecules of potassium hydroxide combine with one atom of sulfuric acid. The two potassium atoms go to the sulfate ion, which is a charged particle consisting of a single sulfur atom bonded to four oxygen atoms from the sulfuric acid, and the two hydrogen atoms from the acid molecule combine with the two oxygen atoms and the two hydrogen atoms left over from the potassium hydroxide ion to make two molecules of water.
When sulfuric acid and potassium hydroxide combine, the products of the reaction are both much safer than the inputs. Water is, of course, a useful compound which is neither corrosive nor poisonous. Potassium sulfate is the one of the world's most popular fertilizers. Potash of sulfur, which is an alternate name for potassium sulfate, delivers both potassium and sulfur to growing plants without inundating them with potentially damaging chlorine, like the other popular type of potash, potassium chloride.