Why are decomposition reactions called opposite of combination reactions? Write equations for these

English

Gujarati

Hindi

1. Chemical Reactions and Equations

medium

Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.

Option A

Option B

Option C

Option D

Solution

Decomposition reactions are those in which a compound breaks down to form two or more substances. These reactions require a source of energy to proceed. Thus, they are the exact opposite of combination reactions in which two or more substances combine to give a new substance with the release of energy.

Decomposition reaction : $AB +$ Energy $\longrightarrow A + B$

$2{{H}_{2}}{{O}_{(l)}}\xrightarrow{\text{ Electroly}sis}2{{H}_{2(g)}}+{{O}_{2(g)}}$

Combination reaction : $A+B \longrightarrow A B+$ Energy

$2{{H}_{2(g)}}+{{O}_{2(g)}}\to 2{{H}_{2}}{{O}_{(l)}}\,+$ Energy

Standard 10

Science

A shiny brown coloured element $‘X’$ on heating in air becomes black in colour. Name the element $‘X’$ and the black coloured compound formed.

hard

Balance the following chemical equations.

$(a)$ $HNO _{3}+ Ca ( OH )_{2} \longrightarrow Ca \left( NO _{3}\right)_{2}+ H _{2} O$

$(b)$ $NaOH + H _{2} SO _{4} \longrightarrow Na _{2} SO _{4}+ H _{2} O$

$(c)$ $NaCl + AgNO _{3} \longrightarrow AgCl + NaNO _{3}$

$(d)$ $BaCl _{2}+ H _{2} SO _{4} \longrightarrow BaSO _{4}+ HCl$

medium

Give an example of a double displacement reaction other than the one given in image.

medium

Which of the statements about the reaction below are incorrect ?

$2 PbO _{( s )}+ C _{( s )} \longrightarrow 2 Pb _{( s )}+ CO _{2( g )}$

$(a)$ Lead is getting reduced.

$(b)$ Carbon dioxide is getting oxidised.

$(c)$ Carbon is getting oxidised.

$(d)$ Lead oxide is getting reduced.

easy

Why should a magnesium ribbon be cleaned before burning in air ?

medium

Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.

Solution

Similar Questions

A shiny brown coloured element $‘X’$ on heating in air becomes black in colour. Name the element $‘X’$ and the black coloured compound formed.

Give an example of a double displacement reaction other than the one given in image.

Which of the statements about the reaction below are incorrect ? $2 PbO _{( s )}+ C _{( s )} \longrightarrow 2 Pb _{( s )}+ CO _{2( g )}$ $(a)$ Lead is getting reduced. $(b)$ Carbon dioxide is getting oxidised. $(c)$ Carbon is getting oxidised. $(d)$ Lead oxide is getting reduced.

Why should a magnesium ribbon be cleaned before burning in air ?

Start a Free Trial Now

Which of the statements about the reaction below are incorrect ?

$2 PbO _{( s )}+ C _{( s )} \longrightarrow 2 Pb _{( s )}+ CO _{2( g )}$

$(a)$ Lead is getting reduced.

$(b)$ Carbon dioxide is getting oxidised.

$(c)$ Carbon is getting oxidised.

$(d)$ Lead oxide is getting reduced.