Tag: chemistry

Questions Related to chemistry

The first fullerene was discovered in :

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

  1. $1970$

  2. $1967$

  3. $1997$

  4. $1985$

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Correct Option: D
Explanation:

The first fullerene was discovered in 1985 by Sir Harold W.Kroto, Smalley and Robert F.Curl. They obtained a cage like molecules composed of 60 carbon atoms.

The most common fullerene is $C {60}$. 60 C-atoms are arranged in _____ pentagons and ______ hexagons.

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

  1. $12, 20$

  2. $16, 26$

  3. $12, 40$

  4. $16, 40$

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Correct Option: A
Explanation:

60 carbon atoms are joined together by single and double bonds to form a hollow sphere with 12 pentagonal and 20 hexagonal faces, a design that resembles a football.

Chemically, diamond is :

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

  1. a mixture of metal carbonates

  2. pure carbon

  3. a pure form of sand

  4. a mixture of calcium and magnesium phosphates

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Correct Option: B
Explanation:

Diamond is an allotrope of carbon and it is present in pure form since it contains carbon atoms tetrahedrally bonded to each other.

Which of the following statement is true for graphite?


(a) In graphite, each carbon atom is bonded to four other carbon atoms.
(b) Graphite is very hard.
(c) It is a good conductor of electricity.
(d) It is bad conductor of electricity.

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

  1. a, b and d

  2. only c

  3. a and d

  4. a and c

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Correct Option: B
Explanation:

The  statement C is  true for graphite.
(a) In graphite, each carbon atom is bonded to three other carbon atoms.
(b) Graphite is soft.
(c) It is a good conductor of electricity as delocalised electrons are free to move in delocalised molecular orbitals.

Which of the following substance consists of only one element?

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

  1. Diamond

  2. Glass

  3. Marble

  4. Sand

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Correct Option: A
Explanation:

Diamond is the purest form of carbon while glass is composed of silica, sodium carbonate. Marble is calcium carbonate and sand is silicon dioxide.

The allotrope of carbon which is a good conductor of heat and electricity is:

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

  1. diamond

  2. sugar charcoal

  3. graphite

  4. wood charcoal

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Correct Option: C
Explanation:

Graphite is an allotrope of carbon other than diamond. 


It has planar structure in which three electrons are covalently bonded while the fourth electron is free to migrate in the layered structure and makes graphite electrically conductive.

Hence, option $C$ is correct.

Rhombic and monoclinic sulphur are:

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

  1. isomers of sulphur

  2. isotopes of sulphur

  3. allotropes of sulphur

  4. isobars of sulphur

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Correct Option: C

The allotrope of carbon used in nuclear reactor is :

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

  1. graphite

  2. diamond

  3. coke

  4. sugar charcoal

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Correct Option: A
Explanation:

Graphite is the most stable form of carbon under standard conditions. Special grades of synthetic graphite also used as neutron moderator within nuclear reactor. Its low neutron cross-section also recommends its use in proposed fusion reactors.

Some elements show the property of existing in two or more distinct physical form which show different physical properties but same chemical properties. These distinct forms of an element are called :

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

  1. isomers

  2. allotropes

  3. compounds

  4. isobars

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Correct Option: B
Explanation:

Allotropes of carbon have a different physical form but chemically they are similar, e.g., diamond and graphite are allotropes of carbon which are chemically carbon compounds but physically diamond is the hardest material known while graphite is soft material.


Hence, option $B$ is correct,

An allotropic form of carbon used for cutting and drilling is which of the following?

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

  1. charcoal

  2. bone charcoal

  3. graphite

  4. diamond

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Correct Option: D
Explanation:

The dominant industrial use of diamond is in cutting, drilling (drill bits), grinding. It is used for these purposes due to its hardness.