Tag: allotropes of carbon

Questions Related to allotropes of carbon

Diamond and graphite are the covalent compounds of carbon element (C).

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. True

  2. False

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Correct Option: A
Explanation:
The giant molecular structure of carbon is lattices made up of carbon which are covalently bonded. These bonds are very strong due to which they are hard and have high melting points. 

Diamond is an allotrope of carbon in which the carbon atoms are arranged in cubic lattice or diamond lattice. In diamond, each carbon atom has four neighbors joined to it with covalent bonds. 

In graphite, the carbon atoms are arranged hexagonally in a planar condensed ring system. The layers are stacked parallel to each other.  The atoms within the rings are bonded covalently, whilst the layers are loosely bonded together by van der Waals forces. 

Therefore, Diamond and graphite are the covalent compounds of carbon element (C).

$C _{graphite}+O _{2(g)}\rightarrow CO _{2(g)}; \Delta H=-393.5kJ, \Delta H$ of the reaction cannot be:

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. Heat of formation of $CO _{2}$

  2. Heat of combustion of $CO _{2}$

  3. Heat of reaction

  4. Heat of transition

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Correct Option: D
Explanation:

$C(graphite)+O _2(g)\longrightarrow CO _2(g)$


Now, here $\Delta H$ of the reaction cannot be the heat of transition, because there is no transition between phase take place at constant temperature and pressure.

For example: transition of $C _{diamond}\to C _{graphite}$

Select the compound from the following which dissolves in water:

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. $CCl _4$

  2. $CS _2$

  3. $C _6H _6$

  4. $C _2H _5OH$

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Correct Option: D

Which of the following statements are incorrect?


I.  Diamond is the hardest natural substance known and has very high melting and boiling point. 

II. Iodine is a metal like lithium, sodium, and potassium are so hard that they cannot be cut with a knife. They have high densities and high melting point. 

III. Graphite is a metal.


IV. Most of the non- metals produce acidic oxides while most of the metals produce basic oxides.

V. Graphite is a conductor of electricity.
chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. I, IV and V only

  2. I, III, IV and V only

  3. II and III only

  4. None of these

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Correct Option: C

The property of catenation is strongest in carbon because?

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. Its ionisation potential is low

  2. Its electronegativity is low

  3. The C-C bond energy is high

  4. Its atomic radius is small

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Correct Option: C
Explanation:

Carbon shows the property of catenation as it is small in size and has the ability to form stable covalent bonds with other carbon atoms to form a chain-like structure. The bond energy between the C-C bond is very high which enables them to form a long chain of C-C stable bonds.

What are the two properties of carbon which led to the huge number of carbon compounds we see around us?

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. (i) Catenation (ii) Tetravalency

  2. (i) Catenation (ii) Tri valency

  3. (i) Catenation (ii) Penta valency

  4. (i) Co valency (ii) Di valency

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Correct Option: A
Explanation:

Carbon can form huge number of carbon compounds due to following properties: 

Catenation is  a self linkage property, present in carbon. Because of catenation, carbon can form long chains, branched chains and closed chains.

Tetravalence: It is the state of an atom with four electrons available for covalent chemical bonding in its valence 

Buckminsterfullerene is an allotropic form of:

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. phosphorus

  2. sulphur

  3. carbon

  4. tin

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Correct Option: C
Explanation:

Carbon is capable of forming many allotropes due to its valency.  
Sixty carbon atoms form the shape of a ball like a football with a carbon atom at each corner of the 20 hexagons and 12 pentagons. The buckminsterfullerenes, is also called fullerenes, Fullerenes are molecules of varying sizes composed entirely of carbon, which take the form of a hollow sphere, ellipsoid, or tube.
Option "C" is correct.

In diamond, the bonding between carbon atoms is :

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. co-ordinate

  2. ionic

  3. electrostatic

  4. covalent

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Correct Option: D
Explanation:

In diamond, each carbon atom is covalently bonded to four other carbon atoms. A lot of energy is needed to separate the atoms in diamond. 


This is because covalent bonds are strong and diamond contains many covalent bonds. 

Hence, the correct option is $D$

Diamond is not a good conductor of electricity because :

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. it is very hard

  2. it is structure is very compact

  3. it is not water soluble

  4. it has no free electrons to conduct electric current

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Correct Option: D

Which is/are the characteristic(s) of Diamond?

chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

  1. Opaque

  2. Hardness

  3. Both $A$ and $B$

  4. Conductor of electricity

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Correct Option: B
Explanation:

Diamond is transparent, hard and poor conductor of electricity. In-fact, diamond is hardest known substance on earth. The hardness is due to the presence of strong covalent bonds between C atoms. Hence, the option (B) is the correct answer.