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प्रश्न
How can the rate of the chemical reaction, namely, decomposition of hydrogen peroxide be increased?
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उत्तर
\[\ce{\underset{peroxide}{\underset{Hydrogen}{2H2O}_{2(l)}} -> \underset{water}{2H2O} + \underset{oxygen}{O2\uparrow}}\]
- The decomposition of hydrogen peroxide (H2O2) into water and oxygen takes place slowly at room temperature.
- However, hydrogen peroxide decomposes rapidly in the presence of manganese dioxide (MnO2) powder, which acts as a catalyst.
- Thus, by adding manganese dioxide (MnO2) powder, the rate of a chemical reaction can be increased.
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संबंधित प्रश्न
What does one mean by exothermic reaction? Give example.
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:_________
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?
What type of reaction is represented by the digestion of food in our body?
Give one example of a decomposition reaction which is carried out by applying heat.
What type of reaction is represented by the following equation?
\[\ce{NH4Cl -> NH3 + HCl}\]
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 is meant by a decomposition reaction?
Which of the following can be decomposed by the action of light?
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.
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 is a redox reaction? Explain with an example.
What does one mean by endothermic reaction? Give example.
Identify the type of following reaction :

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.
(a) Design an activity to demonstrate the decomposition reaction of lead nitrate.
(b) Draw labelled diagram of the experimental set-up. List two main observations.
(c) Write balanced chemical equation for the reaction stating the physical state of the reactant and the products.
A student wants to study a decomposition reaction by taking ferrous sulphate crystals. Write two precautions he must observe while performing the experiment.
Classify the following reaction into –
- Direct combination
- Decomposition
- Displacement
- Double decomposition
The reaction is – Zinc hydroxide on heating gives zinc oxide and water.
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.
The chemical reaction in which two or more products are formed from a single reactant is called ______ reaction.
What is electrolysis?
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?
Which one of the following processes involves chemical reactions?
Marble statues are corroded or stained rain water. Identify the main reason.

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.
When lead nitrate is heated strongly in a boiling tube, two gases are liberated and a solid residue is left behind in the test tube.
- Name the type of chemical reaction and define it.
- Write the name and formula of the coloured gas liberated.
- Write the balanced chemical equation for the reaction.
- Name the residue left in the test tube and state the method of testing its nature (acidic/basic).
