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प्रश्न
What is a redox reaction? Explain with an example.
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उत्तर
A redox reaction is a reaction in which oxidation and reduction reactions take place simultaneously.
When copper oxide is heated with hydrogen, then copper metal and water are formed:
In this reaction, CuO is changing into Cu. That is, oxygen is being removed from copper oxide. Oxygen is being added to hydrogen; H2 is changing into H2O. This shows that oxidation and reduction occur together.
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संबंधित प्रश्न
What type of chemical reaction takes place when limestone is heated?
What type of chemical reaction takes place when silver bromide is exposed to sunlight?
State the change in colour observed in following case mentioning the reason:
Silver chloride is exposed to sunlight.
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 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.
How can the rate of the chemical reaction, namely, decomposition of hydrogen peroxide be increased?
Classify the following reaction into –
- Direct combination
- Decomposition
- Displacement
- Double decomposition
The reaction is – Zinc hydroxide on heating gives zinc oxide and water.
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 _________.
Differentiate between the following:
Electrolytic decomposition and photochemical decomposition.
The chemical reaction in which two or more products are formed from a single reactant is called ______ reaction.
Explain the reaction given in the figure.
Photolysis is a decomposition reaction caused by ______
When SO2 gas is passed through a saturated solution of H2S, which of the following reaction occurs?
Balance the following chemical equation and identify the type of chemical reaction.
`"HgO"("s") overset("(heat)")(->) "Hg"("l") + "O"_2("g")`
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.
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).
