What is a Double-replacement Reaction?

A double-replacement reaction, likewise known together a double displacement reaction, is a type of chemistry reaction in which 2 reactants exchange ions to kind two new compounds. Double-replacement reaction takes location in one aqueous solution and typically results in the development of a precipitate. Ionic compounds mostly participate in a double-replacement reaction, so execute acids and also bases. The bonds created in the product compounds space the same type of bonds, as watched in the reactant molecule <1-3>.

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General Equation

The general formula of double-replacement reaction is:

AB + CD → advertisement + BC

When writing an yes, really reaction, the reaction should be balanced. That is often valuable to represent an aqueous systems as aq. And also a precipitate together s/ppt.

Double instead of Reaction

Why walk Double-replacement Reaction Occur?

A double-replacement reaction occurs when two ionic link react. The positive ions (cation) and an adverse ions (anion) of the 2 reactants, which are ionic compounds, exchange their places. The reaction outcomes in two new products, i m sorry are also ionic compounds.

What wake up in a Double-replacement Reaction?

A double-replacement reaction exchanges the cations or anions of two ionic compounds. The 2 compounds space in your aqueous solutions react to form an insoluble precipitate, an insoluble gas, or water.

How to recognize a Double-replacement Reaction?

The easiest method to recognize a double displacement reaction is to check to see whether or no the cations exchanged anions through each other. An additional clue, if the says of matter are cited, is come look for aqueous reactants and also the formation of one hard product since the reaction generally generates a precipitate.

Examples the Double-replacement Reaction

An instance of a double-displacement reaction is the reaction between iron (III) bromide (FeBr3) and sodium hydroxide (NaOH). The products are salt bromide (NaBr) and iron (III) hydroxide (Fe(OH)3) precipitate.

FeBr3 (aq) + 3 NaOH (aq) → Fe(OH)3 (s/ppt.) + 3 NaBr (aq.)

Double instead of Reaction Examples

How to Balance a Double-replacement Reaction?

Consider the reaction between ammonium sulfate ((NH4)2SO4) and also barium nitrate (Ba(NO3)2). The products are barium sulfate (BaSO4) and also ammonium nitrate (NH4NO3).

(NH4)2SO4 (aq) + Ba(NO3)2 (aq) → NH4NO3 (aq) + BaSO4 (s/ppt.)

Here, the over reaction is unbalanced. We keep in mind that the anions SO42- and also NO3– interchange their areas to form the products. However, we discover that there are only one NH4– and one NO3– on the right-hand side and two of every ion top top the left. So, we multiply the link NH4NO3 by 2 to balance the equation.

(NH4)2SO4 (aq) + Ba(NO3)2 (aq) → 2 NH4NO3 (aq) + BaSO4 (s/ppt.)

Double-replacement Reaction Rules

How to Predict a Double-replacement Reaction?

The an essential rule that a double-replacement reaction follows is the solubility rule. This dominion is provided to predict even if it is a precipitate will type or not. The development of a hard precipitate is the driving pressure that provides the reaction proceed in the forward direction. The following table the solubility have the right to be offered to suspect the formation of a precipitate <3>.

Compounds soluble in water


All compound of Li+, Na+, K+, Rb+, Cs+, and also NH4+


All link of NO3− and C2H3O2−


Compounds of Cl−, Br−, and also I−

Ag+, Hg22+, and also Pb2+

Compounds that SO42-

Hg22+, Pb2+, Sr2+, and also Ba2+

Compounds insoluble in water


Compounds of CO32− and also PO43−

Compounds that Li+, Na+, K+, Rb+, Cs+, and NH4+

Compounds that OH−

Compounds that Li+, Na+, K+, Rb+, Cs+, NH4+, Sr2+, and Ba2+

Types the Double-replacement Reaction

There are two varieties of double-replacement reaction <1-5>.

1. Precipitation Reaction

A precipitation reaction occurs once two ionic link are liquified in water and form a new ionic compound that does not dissolve. This new compound settles down in the equipment as a heavy precipitate. The formation of a solid precipitate is the driving force that makes the reaction proceed.


NaCl (aq.) + AgNO3 (aq.) → NaNO3 (aq.) + AgCl (s/ppt.)

The reaction between barium chloride (BaCl2) and sodium sulfate (Na2SO4) results in salt chloride (NaCl) and a white precipitate the barium sulfate (BaSO4).

BaCl2 (aq.) + Na2SO4 (aq.) → NaCl (aq.) + BaSO4 (s/ppt.)

2 KI (aq.) + Pb(NO3)2 (aq.) → 2 KNO3 (aq.) + PbI2 (s/ppt.)

2. Acid-Base Reaction or Neutralization Reaction

The reaction between an acid and a basic is dubbed an acid-base reaction or a neutralization reaction. One aqueous acid-base reaction typically produces water and also a brand-new ionic compound, referred to as a salt. It is preferable come use strong acid and a solid base to ensure the the reaction proceeds in the forward direction.


A mixture of sulfuric acid (H2SO4) and sodium hydroxide (NaOH) produces salt sulfate (Na2SO4) and water (H2O).

H2SO4 (aq.) + 2 NaOH (aq.) → Na2SO4 (aq.) + 2 H2O (l)

A mixture the hydrochloric mountain (HCl) and also sodium hydroxide (NaOH) produces sodium chloride (NaCl) and also water (H2O).

HCl (aq.) + NaOH (aq.) → NaCl (aq.) + H2O (l)

The reaction in between vinegar (acetic acid) (CH3COOH) and baking soda (sodium bicarbonate) (NaHCO3) to produce carbonic mountain (H2CO3) and also sodium acetate (CH3COONa).

NaHCO3 (aq.) + CH3COOH (aq.) → H2CO3 (aq.) + CH3COONa (aq.)

The carbonic mountain is unstable. It experience decomposition reaction and releases carbon dioxide (CO2), i m sorry is responsible because that the fizz led to by the reaction.

H2CO3 (aq.) → CO2 (g) + H2O (l)

Another form of Double-replacement Reaction

Gas Formation

A gas development reaction is one which yields a gas together a product. The gaseous product then bubbles the end of the solution and also escapes into the air.


Na2S (aq.) + 2 HCl (aq.) → 2 NaCl (aq.) + H2S (g)

ZnS (s) + 2 HCl (aq.) → ZnCl2 (aq.) + H2S (g)

Double-replacement Reaction examples in actual Life

The double-replacement reaction can be it was observed in nature and also real life.

The reaction between vinegar and also baking soda has a couple of applications in daily life.

As a cleaning agent, especially to clean the water disposal pipes in the kitchen and also bathroom sinks.Can be accumulated and offered as a chemistry fire extinguisherTo make a chemical volcano.

Some other examples are:

Hard water reacts v soaps resulting in soap scum on the sink or the wall of a bathroom


Q.1. Have the right to a double displacement reaction it is in a oxidization reaction?

Ans. No. For it to it is in a redox reaction, aspects have to readjust oxidation states, and also that go not happen in a dual displacement reaction.

Q.2. What is the difference in between single-replacement and also double-replacement reactions?


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In a single-replacement reaction, a more reactive facet replaces a less reactive aspect from a compound. In a double-replacement reaction, 2 atoms or a team of atoms switch areas to kind new compounds.