Tag: chemistry

Questions Related to chemistry

Which of the following is not an allotrope of carbon?

chemistry occurrence of carbon compounds in nature organic compounds allotropes of carbon versatile nature of carbon

  1. Buckyballs

  2. diamond

  3. graphite

  4. carbon dioxide

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Correct Option: D
Explanation:

Buckyballs, diamond and graphite are allotrops of carbon while carbon dioxide is a compound of carbon.

Which of the following is not an allotropic form of carbon?

chemistry occurrence of carbon compounds in nature organic compounds allotropes of carbon versatile nature of carbon

  1. Fluorine

  2. Fullerene

  3. Diamond

  4. Graphite

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Correct Option: A
Explanation:

Fullerene, graphite and diamond all are different allotrops of carbon.

Fluorine is an entirely different element, whose atomic number is $9$.
Option A is the correct answer.
Fluorine is not an allotrope of carbon.

Carbon forms bonds with another element by :

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

  1. transferring of electrons.

  2. sharing of electrons.

  3. Both A and B.

  4. None of the above.

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Correct Option: B
Explanation:

Carbon shares electrons while making compounds. It do not transfers electrons to other ions.


Hence, the correct option is $B$.


Which of the following is the true statement for carbon atoms :

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

  1. A carbon atom loses $4$ electrons.

  2. A carbon atom forms $4$ covalent bonds.

  3. A carbon atom share the $2$ electrons in the first principal energy level.

  4. A carbon atom gains $4$ electrons.

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Correct Option: B
Explanation:

Carbon atoms form 4 covalent bonds. Carbon (atomic number 6) has electronic configuration $\displaystyle 1s^2 2s^22p^4$ It has $4$ valence electrons which are shared with other atoms to form $4$ covalent bonds.

____________ is the crystalline allotrope of carbon.

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

  1. Coal

  2. Coke

  3. Diamond

  4. Graphite

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Correct Option: C
Explanation:

Graphite is one of three forms of crystalline, or crystal-forming, carbon. Carbon also exists in an amorphous, or “shapeless,” form in substances such as coal and coke. Different forms of the same element are called allotropes. Besides graphite, the other allotropes of crystalline carbon are diamond and fullerenes


Hence, the correct options are $C$ and $D$

Which of the following elements shows allotropy ?

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

  1. Mg

  2. Cs

  3. Sn

  4. Zn

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Correct Option: C
Explanation:

Allotropy is a phenomenon wherein an element especially from group $13$ to group $16$ exists in more than one form. These forms differ in arrangement of atoms in their crystalline form. Few list of various elements showing allotropy -

 

Forms | | --- | --- | | Carbon : | Graphite, Diamond, Fullerenes | | Sulphur $(S _{8})$: | Rhombic, Monocline, Triclinic sulphur | | Phosphorous $(P _{4})$:  | Red, Black, Yellow | | Tin $(Sn)$: | White, Grey |

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