Question

Explain with the help of examples:
(a) Single displacement reaction:
(b) Decomposition reaction:
(c)
Double displacement reaction:
(d) Neutralization reaction:​

Answer 1

a) Single 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.

Zn + FeSO4 → ZnSO4 + Fe

Zinc displaces iron from Iron sulphate in it's aqueous solution and gives Zinc sulphate and Iron metal.

• General equation for displacement reaction is A + BC → B + AC.
• Definition: More reactive element displaces less reactive element from it's salt solution.

b) Decomposition Reaction

CaCO3 + Heat → CaO + CO2 (Thermal Decomposition Reaction)

2AgCl + Sunlight → 2Ag + Cl2 (Photo Decomposition Reaction)

2H2O + electricity → 2H2 + O2 (Electric Decomposition Reaction)

• General equation for Decomposition Reaction is AB → A + B.
• Definition: When a single reactant break down into two or more products is known as Decomposition reaction.

c) Double Displacement Reaction

Mg + 2HCl → MgCl2 + H2

BaCl2 + Na2SO4 → BaSO4 + 2NaCl

• General equation for double displacement reaction is AB + CD → AD + CB.
• Definition: Reaction in which exchange of ions takes place.

d) Neutralization Reaction

NaOH + HCl → NaCl + H2O

KOH + HCl → KCl + H2O

• General equation for Neutralization reaction is AB + CD → AD + CB.
• Acid and a base are neutralising each other to form salt and water. 

Answer 2

$\bigstar$ $\sf{\purple{\underline{\underline{\orange{Answer:-}}}}}$

$\tt{\underline{\red{\:(a)\:Single\:Displacement\:Reaction\::\:}}}$

• A Single Displacement Reaction, is a Chemical reaction in which one element replaces other element in a Compound .

☞ It can be represented as:

$\tt{\checkmark{\:A\:+\:(B-C)\:→\:(A-C)\:+\:B\:}}$

• The above equation exists when “A” is more reactive than “B” .

╬ Examples:-

1. $\tt{\:Zn\:(s)\:+\:2HCl\:(aq)\:→\:ZnCl_{2}\:(aq)\:+\:H_2\:(g)\:}$
2. $\tt{\:Cu\:+\:2AgNO_3\:→\:2Ag\:+\:Cu(NO_3)_2\:}$

$\tt{\underline{\red{\:(b)\:Decomposition\:Reaction\::\:}}}$

• A Decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds.

╬ Examples:-

1. $\tt{\:2H_2O_2\:→\:2H_2O\:+\:O_2\:}$
2. $\tt{\:H_2CO_3\:→\:H_2O\:+\:CO_2\:}$

$\tt{\underline{\red{\:(c)\:Double\:Displacement\:Reaction\::\:}}}$

• The reaction in which two atoms or group of atoms are displaced by another atom in a molecule is called as Double Displacement Reaction .

$\tt{\checkmark\:{\:(A-B)\:+\:(C-D)\:→\:(A-C)\:+\:(B-D)\:}}$

In the above, “A” and “B” have to be either,

• Halogen, where ‘C’ indicates a Cation .
• Different, where ‘C’ indicates an Anion .

╬ Examples:-

1. $\tt{\:AgNO_{3}\:+\:NaBr\:→\:NaNO_{3}\:+\:AgBr\:}$
2. $\tt{\:BaCl_{2}\:+\:H_{2}SO_{4}\:→\:BaSO_{4}\:+\:2\:HCl\:}$

$\tt{\underline{\red{\:(d)\:Neutralization\:Reaction\::\:}}}$

• The reaction of an Acid and a Base is called as Neutralization Reaction

$\tt{\checkmark\:{\:(Acid)\:+\:(Base)\:→\:(Water)\:+\:(Salt)\:}}$

╬ Examples:-

1. $\tt{\:HCl\:(aq)\:+\:KOH\:(aq)\:→\:H_{2}O\:(l)\:KCl\:(aq)\:}$
2. $\tt{\:2HNO_{3}\:(aq)\:+\:BaSO_{4}\:(aq)\:→\:2H_{2}O\:(l)\:+\:Ba(NO_{3})_{2}\:(aq)\:}$