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प्रश्न
(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.
उत्तर
Activity to demonstrate the decomposition reaction of lead nitrate Pb(NO3)2
(a)
- Take about 2g of lead nitrate powder in a boiling tube.
- Hold the boiling tube with a pair of tongs and heat it over a flame, as shown in the figure.
- What do you observe? Note down the change, if any.
(b)
Two main observations:
- The emission of brown fumes of NO2 after thermal decomposition of Pb(NO3)2.
- The colourless compound Pb(NO3)2 forms a yellow compound PbO and brown fumes of NO2 gas.
(c)
\[\ce{\underset{(Lead nitrate)(solid)}{2Pb(NO3)2_{(s)}} ->[Heat]\underset{(Lead oxide)(solid)}{2PbO_{(s)}} + \underset{(Nitrogen dioxide)(gas)}{4NO2_{(g)}} + \underset{(Oxygen)(gas)}{O2_{(g)}}}\]
APPEARS IN
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 one equation for decomposition reactions where energy is supplied in the form of heat.
What type of reaction is represented by the following equation?
NH4 CI → NH3 + HCI
What is a decomposition reaction?
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.
(a) What do you think metal M is?
(b) What could be gas X2?
(c) Name the metal salt MX.
(d) Name any two salt solutions which on mixing together can produce a precipitate of salt MX.
(e) What type of chemical reaction takes place when salt MX is exposed to light? Write the equation of the reaction?
What are thermal decomposition reactions ? Explain with 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.
Give a balanced equation for –
A double decomposition neutralization reaction involving an acid and a base
Chemical volcano is an example of ______ type of 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).
