What are double decomposition reactions?

Question

Olivia Anton · Accepted Answer

A double decomposition reaction is a reaction in which the positive ions and negative ions in two compounds switch partners to form two new compounds.

The equation is often written in the general form

#"AB + CD" → "CB + AD"#

The older term double decomposition has been largely replaced by the terms double displacement, double replacement, and metathesis.

Many double decomposition reactions are precipitation reactions.

#color(blue)("Ag")color(red)("NO"_3)"(aq)" + color(orange)("Na") color(green)("Cl")"(aq)" → color(blue)("Ag") color(teal)("Cl")"(s)" + color(orange)("Na") color(red)("NO"_3)"(aq)"#

Others are acid-base neutralization reactions.

# color(blue)("H")color(red)("Cl")"(aq)" + color(orange)("Na") color(green)("OH")"(aq)"→ color(orange)("Na")color(red)("Cl")"(aq)" + color(blue)("H") color(green)("OH")"(l)"#

Here is a good video on double replacement reactions.

Peyton Adams · Answer

undefined In double decomposition reactions, two reactants exchange ions, resulting in the creation of two new compounds.

Serenity Allen · Answer

undefined Double decomposition reactions, also known as double displacement or metathesis reactions, occur when parts of two different compounds exchange places, resulting in the formation of two new compounds. In double decomposition reactions, the cations and anions of two compounds switch places to form new combinations. This exchange typically occurs when one of the products formed is insoluble and precipitates out of solution, driving the reaction forward. Double decomposition reactions often occur in aqueous solutions and can be represented by the general chemical equation:

AB + CD → AD + CB

Where A, B, C, and D represent different elements or groups of elements. The reaction proceeds as the cation of one compound combines with the anion of the other compound to form two new compounds.

An example of a double decomposition reaction is the reaction between silver nitrate (AgNO3) and sodium chloride (NaCl) to form silver chloride (AgCl) and sodium nitrate (NaNO3):

AgNO3 (aq) + NaCl (aq) → AgCl (s) + NaNO3 (aq)

In this reaction, the silver cation (Ag+) from silver nitrate combines with the chloride anion (Cl-) from sodium chloride to form insoluble silver chloride, which precipitates out of solution, while sodium nitrate remains dissolved in the solution.