Tag: allotropes of carbon

Questions Related to allotropes of carbon

Which of the following can conduct electricity in the solid state ?

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

  1. Sucrose, $C _{12}H _{22}O _{11}$(s)

  2. Graphite, C(s)

  3. Sodium hydroxide, NaOH(s)

  4. Iron(III) chloride, $FeCl^3$(s)

  5. Iodine, $I _2$(s)

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Correct Option: B
Explanation:

Graphite, C(s) can conduct electricity in the solid state.
Ferric chloride and sodium hydroxide are ionic solids which do not conduct electricity in solid state.
They conduct electricity in molten state or in aqueous solution.
Iodine and sucrose are molecular solids which do not conduct electricity.
Graphite is a network solid and conducts electricity as it has delocalised molecular orbitals in which delocalised electrons are free to move.

Which one has an allotrophic form that is a good electrical conductor at standard conditions ?

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

  1. Carbon

  2. Nitrogen

  3. Oxygen

  4. Neon

  5. Argon

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Correct Option: A
Explanation:

Carbon has an allotrophic form that is a good electrical conductor at standard conditions.
This allotrope is graphite.

Which of the following element's allotrop is the primary absorber of UV solar radiation in Earth's atmosphere ?

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

  1. Carbon

  2. Nitrogen

  3. Ozone

  4. Neon

  5. Argon

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Correct Option: C
Explanation:

Ozone, an allotrope of oxygen is the primary absorber of UV solar radiation in Earth's atmosphere.


Hence option C is correct.

In which of the given pairs the two compounds are allotropes of the same element?

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

  1. $Br _{2}$ and $Hg$

  2. $Cl _{2}$ and $F _{2}$

  3. $NH _{4}^{+}$ and $H _{3}O^{+}$

  4. $Fe$ and $CO$

  5. Diamond and graphite

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Correct Option: E
Explanation:

Diamond and graphite are allotropes of each other.
They are are allotropes of carbon. Allotropes are different forms of same element. Another allotrope of carbon is fullerene.

The number of free electrons in the outermost shell of carbon in graphite is:

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

  1. four

  2. one

  3. two

  4. three

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Correct Option: B
Explanation:

The number of free electrons in the outermost shell of carbon in graphite is one. Each $\displaystyle C$ atom is $\displaystyle sp^2$ hybridised. Each $\displaystyle C$ atom forms 3 covalent bonds with 3 other $\displaystyle C$ atoms. Thus, each $\displaystyle C$ atom has one electron in unhybridized $\displaystyle 2p$ orbital which it uses for $\displaystyle \pi $ bonding.

Select the correct statement.

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

  1. Carbon-carbon bond order in graphite is more than diamond

  2. Carbon-carbon bond order in graphite is less than diamond

  3. Hybridization of each carbon in diamond is ${sp}^{2}$

  4. Hybridization of each carbon in graphite is ${sp}^{3}$

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Correct Option: A
Explanation:

Hybridization of carbon is $sp^2$ in graphite as $1$ carbon atom is joined to $3$ other carbon atoms. In diamond, the hybridization is $sp^3$ as $1$ carbon atom is joined to $4$ other carbon atoms.

Bond order= $\cfrac {\text {Total number of valence electrons of carbon}}{\text {number of }\sigma\text { bonds}}$
For graphite, $B.O= \cfrac {4}{3}= 1.33$,
For diamond, $B.O= \cfrac {4}{4}=1$ .
Hence, Bond order for graphite is more than that for diamond.

Which of the following statements is/are correct?


(1) Graphite is used in making electrodes because it can conduct electricity.
(2) Graphite is used as a solid lubricant.
(3) Graphite is used in the manufacture of crucibles.
(4) Graphite is also known as black lead.

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

  1. 1 and 4

  2. 2 and 3

  3. 1 and 2

  4. All of them

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Correct Option: D
The phenomenon of existence of an element in more than one physical form is called allotropy.
chemistry carbon and its compounds organic compounds allotropes of carbon versatile nature of carbon

  1. True

  2. False

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Correct Option: A
Explanation:

Allotropy or allotropism is the property of some chemical elements to exist in two or more different forms, known as allotropes of these elements.

Example : Graphite and diamond