Advertisements
Advertisements
Question
A student wants to study a decomposition reaction by taking ferrous sulphate crystals. Write two precautions he must observe while performing the experiment.
Solution
Precautions for the decomposition reaction of reffous sulphate crystals.
\[\ce{\underset{\text{(Light Green)Feffous sulphate crystals}}{FeSO4.7H2O} ->[\Delta] \underset{\text{(white)Anhydrous ferrous sulphage}}{FeSO4} ->[\Delta] \underset{\text{(Brown)Ferric Oxide}}{Fe2O3} + SO2 + SO3}\]
(1) The mouth of the boiling tube should not be at pointed.
(2) Waft gases are emitted from FeSO4 on heating . The gases SO2 and SO3 are very harmful , so deep breath should not be taken when smelling the odour of the gases .
(3) Test tube holder must be used while heating the test tube.
APPEARS IN
RELATED QUESTIONS
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 is the colour of ferrous sulphate crystals? How does this colour change after heating?
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.
Classify the following reaction into –
- Direct combination
- Decomposition
- Displacement
- Double decomposition
The reaction is – Zinc hydroxide on heating gives zinc oxide and water.
Give a balanced equation for –
An electrolytic decomposition reaction involving a neutral liquid
Differentiate between the following:
Electrolytic decomposition and photochemical decomposition.
Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is:
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?
