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प्रश्न
What does one mean by endothermic reaction? Give example.
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उत्तर १
Reactions in which energy is absorbed are known as endothermic reactions.
Example: \[\ce{N2(g) + O2(g) + Heat -> 2NO(g)}\]
\[\ce{2NH3(g) + Heat -> N2(g) + 3H2(g)}\]
उत्तर २
A reaction in which heat is absorbed is called an endothermic reaction.
Example: When silver chloride is left in the sunlight, it absorbs heat and turns grey because of the formation of silver metal.
\[\ce{2AgCl(s)->[Sunlight] 2Ag(s) + Cl2(g)}\]
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- 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.
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- 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.
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