Advertisements
Advertisements
प्रश्न
Differentiate between the following:
Electrolytic decomposition and photochemical decomposition.
Advertisements
उत्तर
- Electrolytic decomposition: “A decomposition reaction which is brought about by the passage of electric current.”
\[\ce{2H2O->[Electricity][Current]2H2 + O2}\] - Photochemical decomposition: “A decomposition reaction which takes place in presence of light.”
e.g. decomposition of silver salts in the presence of sunlight.
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?
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Write one equation for decomposition reactions where energy is supplied in the form of heat.
Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity
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.
What type of chemical reaction is represented by the following equation?
\[\ce{X -> Y + Z}\]
Explain the following type of chemical reaction, giving two examples for it:
Decomposition reaction
Give a balanced equation for –
A thermal decomposition reaction involving heat on limestone [calcium carbonate]
Explain the reaction given in the figure.
Photolysis is a decomposition reaction caused by ______
