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प्रश्न
A solid element X has four electrons in the outermost shell of its atom. An allotrope Y of this element is used as a dry lubricant in machinery and also in making pencil leads.
(a) What is element X?
(b) Name the allotrope Y.
(c) State whether allotrope Y is a good conductor or non-conductor of electricity.
(d) Name one use of allotrope Y (other than lubrication and pencil leads)
(e) Name two other allotropes of element X.
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उत्तर
(a) The solid element 'X' is carbon, which has four electrons in the outermost shell of its atom.
(b) Graphite is the allotrope 'Y' of carbon which is used as a dry lubricant in machinery, and al in making pencil leads.
(c) Graphite (Y) is a good conductor of electricity because of the presence of free electrons in its crystal.
(d) Graphite (Y) is used in making carbon electrodes or graphite electrodes in dry cells and electric arcs.
(e) Diamond and buckminsterfullerene are the two other allotropes of carbon.
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संबंधित प्रश्न
State the reason to explain why covalent compounds "have low melting and boiling points."
Buckminsterfullerene is spherical molecule in which 60 carbon atoms are arranged in interlocking hexagonal and pentagonal rings of carbon atoms.
How many pentagons of carbon atoms are present in one molecule of buckminsterfullerene?
Give one example of a molecule containing a single covalent bond.
Fill in the blank in the following sentence:
In forming N2 molecule, .............. electrons are shared by each atom of nitrogen.
Why is graphite used for making dry cell electrodes but diamond is not?
How will you find out which of the water soluble compound A or B is ionic?
The organic compound prepared by Wohler from an inorganic compound called ammonium cyanate was:
(a) glucose
(b) urea
(c) uric acid
(d) vinegar
The number of isomers formed by the hydrocarbon with molecular formula C5H12 is:
(a) 2
(b) 5
(c) 3
(d) 4
What are the conditions necessary for the formation of covalent molecules?
An element L consists of molecules.
What type of bonding is present in the particles that make up L?
What is the difference between :
Ionic compounds and covalent compounds
Fill in the blank and rewrite the completed statement:
Covalent compounds are generally soluble in _________ solvents.
Give an example for each of the following statement
A compound in which two Covalent bonds are formed.
Give an example for each of the following statement.
Formation of coordinate covalent bond between NH3 ➝ BF3 molecules
Give an example for each of the following statement.
A compound in which three covalent bonds are formed.
Which of the following statements are correct for carbon compounds?
- Most carbon compounds are good conductors of electricity.
- Most carbon compounds are poor conductors of electricity.
- Force of attraction between molecules of carbon compounds is not very strong.
- Force of attraction between molecules of carbon compounds is very strong.
The correct structural formula of butanoic acid is
What is a covalent bond?
"Carbon prefers to share its valence electrons with other atoms of carbon or with atoms of other elements rather than gaining or losing the valence electrons in order to attain noble gas configuration." Give reasons to justify this statement.
State the reasons, why carbon cannot
- Lose four electrons to form C4+ cation and
- Gain four electrons to form C4- anion.
How does carbon overcome this problem to form compounds?
