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प्रश्न
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
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उत्तर
Decomposition reactions occur when a compound breaks up into two or more simpler substances. On the other hand, combination reactions occur when two or more substances combine to form a single substance.
Thus, decomposition reactions are the opposite of combination reactions.
Decomposition Reactions:
\[\ce{CaCO3(s) -> CaO(s) + CO2(g)}\]
\[\ce{2H2O(l) ->[Electricity] 2H2(g) + O2(g)}\]
Combination Reactions:
\[\ce{2H2(g) + O2(g) -> 2H2O(l)}\]
\[\ce{NH3(g) + HCl(g) -> NH4Cl(s)}\]
APPEARS IN
संबंधित प्रश्न
What does one mean by exothermic reaction? Give example.
Give one example of a decomposition reaction which is carried out by applying heat.
Give one example of a decomposition reaction which is carried out with electricity.
What type of reaction is represented by the following equation?
NH4NO2 → N2 + 2H2O
When a green iron salt is heated strongly, its colour finally changes to brown and odour of burning sulphur is given out.
(a) Name the iron salt.
(b) Name the type of reaction that takes place during the heating of iron salt.
(c) Write a chemical equation for the reaction involved.
Explain the following type of chemical reaction, giving two examples for it:
Decomposition reaction
How will you obtain Nitrogen dioxide from lead nitrate.
Also give balanced equations for the reactions
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Thermal decomposition of a substance is brought about with the help of
- reactants
- water
- wind
- heat
What do you mean by redox reaction ? Explain with the help of an example.
What does one mean by endothermic reaction? Give example.
Study the following figure and answer questions.
a) After heating Calcium carbonate, which gas is formed in a test tube?
b) When we pass this gas through limewater what change, did you observe?
c) Write down the chemical reaction showing the product formation after heating the Calcium carbonate.
Differentiate between direct combination reaction and a decomposition reaction.
Give a balanced equation for –
A double decomposition neutralization reaction involving an acid and a base
Give a balanced equation for the following type of reaction:
A thermal decomposition reaction in which a metallic nitrate decomposes to give – a basic oxide.
Explain the reaction given in the figure.
Chemical volcano is an example of ______ type of reaction.
The following reaction is used for the preparation of oxygen gas in the laboratory:
\[\ce{2KClO3_{(s)} ->[Heat] 2KCl + 3O2_{(g)}}\]
Which of the following statement about the reaction is correct?
Give the ratio in which hydrogen and oxygen are present in water by volume.
Assertion: Decomposition of vegetable matter into compost is an endothermic reaction.
Reason: Decomposition reaction involves breakdown of a single reactant into simpler products.
These consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Silver bromide decomposition is used in black and white photography.
Reason: Light provides energy for this exothermic reaction.
