(a) Why are decomposition reactions called the opposite of combination reactions? Explain with equations of these reactions.(b) Express the following facts in the form of a balanced chemical equation:"When a strip of copper metal is placed in a solution of solver nitrate, metallic silver is precipitated and a solution containing copper nitrate is formed."

Academic Chemistry NCERT Class 10

(a) Decomposition reactions: The reactions in which a compound splits up into two or more simpler substances when energy is provided to it is known as decomposition reactions.

Example: When calcium carbonate is heated, it decomposes to give calcium oxide and carbon dioxide.

$CaCO_{3}\xrightarrow{Heat} CaO+CO_{2}$

Decomposition reactions are called opposite of combination reactions because, in a combination reaction, two or more substances combine with the release of energy to form a single substance.

Example: Carbon combines with oxygen to produce carbon dioxide and energy is released in this process.

$C\ ( s) \ +\ O_{2} \ ( g) \ \rightarrow \ CO_{2} \ +\ Heat$

(b) When a strip of copper metal is placed in a solution of silver nitrate, metallic silver is precipitated and a solution containing copper nitrate is formed

$Cu\ ( s) \ +\ 2AgNO_{3} \ ( aq) \ \ \rightarrow Cu( NO_{3})_{2} \ ( aq) \ +\ 2Ag\ ( s)$

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Updated on: 10-Oct-2022

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