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प्रश्न
On heating blue coloured powder of copper (II) nitrate, in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed
- Write a balanced chemical equation of the reaction.
- Identify the brown gas X evolved.
- Identify the type of reaction.
- What could be the pH range of aqueous solution of the gas X?
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उत्तर
- `underset("Copper (II) nitrate")(2"Cu"("NO"_3)_2)("s") overset "(Heat)"(->) underset "(Black)" (2"CuO"("s")) + underset(X)(4"NO"_2("g")) + "O"_2("g")`
- Brown gas (X) is nitrogen dioxide.
- It is an example of decomposition reaction.
- Nitrogen dioxide is an acidic oxide. Therefore, it dissolves in water to form an acidic solution. The pH of the solution is expected to be less than 7.
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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?
Write the balanced chemical equation for the following and identify the type of reaction.
\[\ce{Zinc carbonate(s) -> Zinc oxide(s) + Carbon dioxide(g)}\]
Write one equation for decomposition reactions where energy is supplied in the form of heat.
A solid substance P which is very hard is used in the construction of many buildings, especially flooring. When substance P is heated strongly, it decomposes to form another solid Q and a gas R is given out. Solid Q reacts with water with the release of a lot of heat to form a substance S. When gas R is passed into a clear solution of substance S, then a white precipitate of substance T is formed. The substance T has the same chemical composition as starting substance P.
- What is substance P? Write its common name as well as chemical formula.
- What is substance Q?
- What is gas R?
- What is substance S? What is its clear solution known as?
- What is substance T? Name any two natural forms in which substance T occurs in nature.
Give one example of a decomposition reaction which is carried out by applying heat.
What type of chemical reaction is represented by the following equation?
\[\ce{X -> Y + Z}\]
What is meant by a decomposition reaction?
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{Zn_{(s)} + H2SO4 -> ZnSO4_{(s)} + H2_{(g)}}\]
Explain the following type of chemical reaction, giving two examples for it:
Decomposition reaction
How will you obtain Nitrogen dioxide from lead nitrate.
Also give balanced equations for the reactions
What does one mean by endothermic reaction? Give example.
Identify the type of following reaction :
Differentiate between the following:
Electrolytic decomposition and photochemical decomposition.
Electrolysis is type of ______ reaction.
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).
Write one equation for the decomposition reaction where energy is supplied in the form of light.
