Last updated on February 6th, 2024 at 12:52 pm
CG Board Class 8 Carbon
Chhattisgarh Board Class 8 Science Chapter 6 Solution Textbook question and answers as well as extra question and answers from the chapter
Choose the correct answer :-
1. Graphite is not used :-
(a) As lubricant (b) In electrodes
(c) In pencil lead (d) In cutting instrument.
2. Carbon dioxide converts blue litmus into red, thus it is an :-
(a) Acidic oxide (b) Alkaline/basic oxide
(c) neutral oxide (d) none of these.
3. Carbon allotrope with 60 atom is :-
(a) Fullerene (b) Graphite
(c) Diamond (d) Charcoal
4. Dry ice is :-
(a) Solid CO2 (b) liquid CO2
(c) Gaseous CO2 (d) Solid CO
5. The hardest substance in nature is :-
(a) Graphite (b) Stone
(c) Diamond (d) Charcoal
6. Which zone of the flame has the highest temperature?
(a) Inner dark zone (b) Shining and bright middle zone
(c) Light blue zone (d) Unlighted zone
7. Allotropy is a characteristic of : –
(a) Element (b) Compound
(c) Mixture (d) All of the above
Fill in the blanks :-
1. Combination of __________ produces flame.
2. Because of its softness ________ is used in pencil lead.
3. _________ is the hardest allotropic form of carbon.
4. Carbon dioxide is a ______ , _______ gas.
Combination of fuel and oxygen produces flame.
Because of its softness graphite is used in pencil lead.
Diamond is the hardest allotropic form of carbon.
Carbon dioxide is a colorless, odorless gas.
Say whether the following statements are correct or wrong. Correct the wrong statements.
1. Both graphite and diamond have the same element, carbon in it. [Correct]
2. Diamond is a good conductor of electricity.[Wrong]
(Corrected: Diamond is a poor conductor of electricity.)
3. The light blue zone in flame is in the middle of the flame.[Wrong]
(Corrected: The light blue zone in the flame is at the outermost part of the flame.)
4. Combustion doesn’t take place in the outer zone of the flame.[Wrong]
(Corrected: Combustion takes place in all zones of the flame, including the outer zone.)
5. Carbon dioxide is of alkaline nature.[Wrong]
(Corrected: Carbon dioxide is an acidic oxide, not alkaline.)
Match the following :-
- Lamp black and charcoal: Carbon allotrope
- Made of 60 carbon atoms: Fullerene
- Hardest substance: Diamond
- Dry ice: Solid carbon dioxide
- Combustion: Oxidation
Answer the following questions :-
(1) What do you understand by allotropy? What are the different allotropes of carbon? Write two uses of each?
Different forms of an element having different physical properties but the same chemical properties are called allotropes. In this way the property of an element having different forms is called allotropy.
(2) How will you differentiate between graphite and diamond?
Graphite:
Made up of layers of carbon atoms arranged in hexagonal rings.
Soft and slippery to the touch.
Conducts electricity due to delocalized electrons between layers.
Diamond:
Consists of carbon atoms arranged in a tetrahedral lattice structure.
Extremely hard and has a crystalline structure.
Does not conduct electricity due to its tightly bound carbon atoms.
(3) What is Fullerene? What are its main uses?
Fullerene is a carbon allotrope composed of carbon atoms arranged in closed, hollow cages or tubes.
Main uses of Fullerene include:
Nanotechnology,Electronics,Medical applications.
(5) What is dry ice? What are its important uses?
Dry ice is solid carbon dioxide (co2)at temperatures below -78.5°C.
Important uses of dry ice include:
Cooling agent,Special effects,Industrial cleaning,Carbonation.
