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प्रश्न
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?
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उत्तर
(a) Compound A is potassium chlorate (KClO3).
(b) Compound B is potassium chloride (KCl).
(c) Gas C is oxygen gas (O2), which does not burn itself but helps burn other things.
(d) Black substance X is manganese oxide (MnO2). Its function is to catalyse the reaction.
(e) General name of substance like X (MnO2) is catalyst.
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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?
Rewrite the following statements by selecting the correct options:
\[\ce{CaCO3 ->[\Delta] CaO + CO2 ^}\] is a __________ reaction.
State an important use of decomposition reactions.
What type of reaction is represented by the following equation?
NH4 CI → NH3 + HCI
What do you mean by redox reaction ? Explain with the help of an 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.
(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.
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 metallic nitrate decomposes to give – a basic oxide.
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.
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.
Which of the following is an endothermic process?
- 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.
A metal nitrate 'A' on heating gives a metal oxide along with evolution of a brown coloured gas 'B' and a colourless gas, which helps in burning. Aqueous solution of 'A' when reacted with potassium iodide forms a yellow precipitate.
- Identify 'A' and 'B'
- Name the types of the reactions involved in the above statement.
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).
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.
