Activity 4.3 Class 10 Science- Explanation

In this activity, we will study the nature of flames of some carbon compounds like naphthalene, camphor and alcohol.

Aim of the activity

 To observe the combustion of carbon compounds

Materials Required

    1. Naphthalene

    2. Camphor

    3. Alcohol

    4. Spatula

    5. Candle

    6. Metal plate

    7. Tongs

    8. Match box

Procedure

We take a small quantity of naphthalene on a spatula and try to burn in flame, observe the colour of flame and smoke produced. Now we hold a metal plate over the flame and see if any deposition (soot) occurs.

 Now we repeat the same above procedure with camphor and alcohol.

Observation

 

Explanation

Naphthalene, camphor and alcohol are carbon compounds. Naphthalene and camphor produce yellow and smoky flame and leave a black soot on the metal plate due to incomplete combustion.

 Carbon particles get deposit because Carbon does not burn completely

Alcohol is oxygen rich compound so it burns with clean blue flame and does not produce smoke, this is due to complete combustion.

Conclusion

 This activity tells us that substance with carbon but less oxygen undergoes incomplete combustion and oxygen rich substance like alcohol undergo complete combustion.

 

Frequently Asked Questions

   1.  Why does naphthalene produce soot when burnt?

Answer – Naphthalene contains high percentage of carbon and undergoes incomplete combustion.so it produces soot.

 

   2. Why is alcohol burn with clean flame?

Answer – Because alcohol contains oxygen so it undergoes complete combustion.

   3. What does black soot on the metal plate indicate?

Answer – This indicates the incomplete combustions of carbon  and deposition of carbon particles on the metal plate.

   4. What are the harmful impact of incomplete combustion?

Answer – Harmful carbon monoxide gas is produced which contribute to air pollution.