Vahetusreaktsioon

Vahetusreaktsioon, also known as double displacement or metathesis reaction, is a chemical reaction where the ions of two compounds exchange places to form two new compounds. The general form of a vahetusreaktsioon can be represented as AB + CD → AD + CB, where A and C are cations and B and D are anions.

These reactions typically occur in aqueous solutions. For a vahetusreaktsioon to proceed and be observable, at least one of the products formed must be removed from the solution. This removal can happen in three main ways: formation of a precipitate (an insoluble solid), formation of a gas, or formation of a molecular compound like water.

Precipitation reactions are a common type of vahetusreaktsioon. When two soluble ionic compounds are mixed, and one of the potential products is insoluble in water, it will precipitate out of the solution. For example, mixing silver nitrate (AgNO3) and sodium chloride (NaCl) in water results in the formation of silver chloride (AgCl), a white precipitate, and sodium nitrate (NaNO3), which remains dissolved. The net ionic equation for this reaction highlights the formation of the precipitate.

Gas-forming reactions involve the production of a gaseous product. For instance, the reaction between an acid and a carbonate produces carbon dioxide gas. The reaction of hydrochloric acid (HCl) with sodium carbonate (Na2CO3) yields sodium chloride (NaCl), water (H2O), and carbon dioxide (CO2), which bubbles out of the solution.

Formation of a molecular compound, most commonly water, is another driving force for vahetusreaktsioon. Acid-base neutralization reactions are a prime example. When an acid reacts with a base, they form a salt and water. The reaction between sulfuric acid (H2SO4) and potassium hydroxide (KOH) produces potassium sulfate (K2SO4) and water (H2O).