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प्रश्न
What is meant by a decomposition reaction?
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उत्तर
A decomposition reaction is a chemical reaction in which a single compound breaks down to simpler products. It is the opposite of a combination reaction.
संबंधित प्रश्न
Write the balanced chemical equation for the following and identify the type of reaction.
\[\ce{Zinc carbonate(s) -> Zinc oxide(s) + Carbon dioxide(g)}\]
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Write one equation for decomposition reactions where energy is supplied in the form of heat.
Taking into consideration the relationship in the first pair, complete the second pair
2H2 + O2 → 2H2O :Combination Reaction :: 2HgO → 2Hg + O2:_________
Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity
Rewrite the following statements by selecting the correct options:
\[\ce{CaCO3 ->[\Delta] CaO + CO2 ^}\] is a __________ reaction.
The white solid compound A decomposes quite rapidly on heating in the presence of a black substance X to form a solid compound B and a gas C. When an aqueous solution of compound B is reacted with silver nitrate solution, then a white precipitate of silver chloride is obtained along with potassium nitrate solution. Gas C does not burn itself but helps burn other things.
- What is compound A?
- What is compound B?
- What is gas C?
- What do you think is the black substance X? What is its function?
- What is the general name of substances like X?
Give one example of a decomposition reaction which is carried out by applying heat.
What type of reaction is represented by the following equation?
\[\ce{2FeSO4 -> Fe2O3 + SO2 + SO3}\]
What type of chemical reaction takes place when silver bromide is exposed to sunlight?
What type of chemical reaction is represented by the following equation?
\[\ce{X -> Y + Z}\]
What type of reaction is represented by the following equation?
\[\ce{NH4NO2 -> N2 + 2H2O}\]
A metal salt MX when exposed to light splits up to form metal M and a gas X2. Metal M is used in making ornaments whereas gas X2 is used in making bleaching powder. The salt MX is itself used in black and white photography.
- What do you think metal M is?
- What could be gas X2?
- Name the metal salt MX.
- Name any two salt solutions which on mixing together can produce a precipitate of salt MX.
- What type of chemical reaction takes place when salt MX is exposed to light? Write the equation of the reaction.
Explain the following type of chemical reaction, giving two examples for it:
Decomposition reaction
What are thermal decomposition reactions ? Explain with an example.
Give a scientific reason.
When the gas formed on heating limestone is passed through freshly prepared lime water, the lime water turns milky.
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.
Answer the following question.
2 g of silver chloride is taken in a china dish and the china dish is placed in sunlight for some time. What will be your observation in this case? Write the chemical reaction involved in the form of a balanced chemical equation. Identify the type of chemical reaction.
Classify the following reaction into different type:
\[\ce{2KClO3(s)->[\Delta] 2KCl(aq) + 3O2(g)}\]
Give a balanced equation for –
An electrolytic decomposition reaction involving a neutral liquid
Give a balanced equation for –
A double decomposition neutralization reaction involving an acid and a base
Give a balanced equation for –
A white precipitate obtained during a double decomposition reaction involving a silver salt with sodium salt.
Complete the statement by filling in the blank with the correct word:
Decomposition of silver salts in the presence of sunlight is an example of _________.
Give a balanced equation for the following type of reaction:
A thermal decomposition reaction in which a compound decomposes to give two new compounds.
Differentiate between the following:
Thermal decomposition and thermal dissociation.
Which one of the following processes involves chemical reactions?
Which among the following statement(s) is (are) true?
Exposure of silver chloride to sunlight for a long duration turns grey due to
(i) the formation of silver by decomposition of silver chloride.
(ii) sublimation of silver chloride.
(iii) decomposition of chlorine gas from silver chloride.
(iv) oxidation of silver chloride.
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.
What is observed when silver chloride is exposed to sunlight? Give the type of reaction involved.
Write one equation for the decomposition reaction where energy is supplied in the form of electricity.
A solution of a substance ‘X’ is used for whitewashing.
- Name the substance ‘X’ and write its formula.
- Write the reaction of the substance ‘X’ named in the above formula with water.
