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प्रश्न
Which of the following can be decomposed by the action of light?
(a) NaCl
(b) KCl
(c) AgCl
(d) CuCl
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उत्तर
(c) AgCl
The chemical reaction is given as follows:
2AgCl (s) → 2Ag (s) + Cl2 (g)
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संबंधित प्रश्न
Why is the amount of gas collected in one of the test tubes in the following Activity double of the amount collected in the other? Name this gas.
- Take a plastic mug. Drill two holes at its base and fit rubber stoppers in these holes. Insert carbon electrodes in these rubber stoppers as shown in the following Fig.
- Connect these electrodes to a 6 volt battery.
- Fill the mug with water such that the electrodes are immersed. Add a few drops of dilute sulphuric acid to the water.
- Take two test tubes filled with water and invert them over the two carbon electrodes.
- Switch on the current and leave the apparatus undisturbed for some time.
- You will observe the formation of bubbles at both the electrodes. These bubbles displace water in the test tubes.
- Is the volume of the gas collected the same in both the test tubes?
• Once the test tubes are filled with the respective gases, remove them carefully. - Test these gases one by one by bringing a burning candle close to the mouth of the test tubes.
Caution: This step must be performed carefully by the teacher.
- What happens in each case?
- Which gas is present in each test tube?

Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
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.
(a) What is compound A?
(b) What is compound B?
(c) What is gas C?
(d) What do you think is the black substance X? What is its function?
(e) What is the general name of substances like X?
What type of chemical reaction take place when electricity is passed through water?
What type of reaction is represented by the following equation?
NH4NO2 → N2 + 2H2O
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{Zn_{(s)} + H2SO4 -> ZnSO4_{(s)} + H2_{(g)}}\]
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 does one mean by endothermic reaction? Give example.
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.

Electrolysis is type of ______ reaction.
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.
Balance the following chemical equation and identify the type of chemical reaction.
`"HgO"("s") overset("(heat)")(->) "Hg"("l") + "O"_2("g")`

- Identify the gasses evolved at the anode and cathode in the above experimental set up.
- Name the process that occurs. Why is it called so?
- Illustrate the reaction of the process with the help of a chemical equation.
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).
Write the molecular formula of calcium carbonate.
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.
