Question

1. What are called combination reaction, decomposition reaction, displacement reaction precipitation reaction.Write one equation for each type of reaction.​

Answer 1

Combination Reaction

CaO + H2O → Ca(OH)2

Calcium oxide and water combine together to form calcium hydroxide (slaked lime). The above reaction is an example of Combination reaction.

• General equation for combination reaction is A + B → AB

Decomposition Reaction

When a single reactant break down into two or more products is known as Decomposition reaction.

Decomposition reaction is of three types.

1. Thermal decomposition reaction

• CaCO3 + Heat → CaO + CO2

2. Photo decomposition reaction

• 2AgCl + Sunlight → 2Ag + Cl2

3. Electric decomposition reaction

• 2H2O + electricity → 2H2 + O2

General equation for Decomposition Reaction is AB → A + B.

Displacement Reaction

Fe + CuSO4 → FeSO4 + Cu

Here, iron displaces copper from copper sulphate in it's aqueous solution and gives ferrous sulphate and copper metal. The above reaction is an example of displacement reaction.

• General equation for displacement reaction is A + BC → B + AC.

Precipitation Reaction

Pb(NO3)2 + 2KI → PbI2 + 2KNO3

The given reaction is an Double Displacement Reaction. As the ions are displacing each other. Also it is a Precipitation Reaction as yellow precipitates of Lead (II) Iodine are formed.

• General equation for precipitation reaction is AB + CD → AD + CB.

Answer 2

Explanation:

✍️ COMBINATION REACTION ✍️

A REACTION IN WHICH A SINGLE PRODUCT IS FORMED FROM TWO OR MORE REACTANTS IS KNOWN AS COMBINATION REACTION.

✏️ Example ✏️

2H2(g) +O2(g)====> 2H2O(l)

✍️ DECOMPOSITION REACTION ✍️

DECOMPOSITION REACTION OPPOSITE OF COMBINATION REACTION. IN A DECOMPOSITION REACTION A SINGLE SUBSTANCE DECOMPOSES TO GIVE TWO OR MORE SUBSTANCE.

✏️ Example ✏️

2FeSO4(s)=====>F32O3(s)+SO2(g)+SO3(g)

✍️ DISPLACEMENT REACTION ✍️

WHEN AN ELEMENT DISPLACES ANOTHER ELEMENT FROM WHICH COMPOUND ,A DISPLACEMENT REACTION OCCURS.

✏️ Example ✏️

Fe(s)+CuSO4(aq)====>FeSO4(aq)+Cu(s)

✍️ PRECIPITATION REACTION ✍️

THIS INSOLUBLE SUBSTANCE FORMED IS KNOWN AS A PRECIPITATE ANY REACTION THAT PRODUCES A PRECIPITATE CAN BE CALLED AS PRECIPITATION REACTION.

✏️ Example ✏️

Na2SO4(aq)+BaCl2(aq)====>BaSO4(s)+2NaCl(aq)