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प्रश्न
Name the hardest natural substance known.
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उत्तर
Diamond is the hardest natural substance known.
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संबंधित प्रश्न
Write structural formula of Methane.
Choose the most appropriate answer from the following list of oxides which fit the description.
A covalent oxide of a metalloid.
What type of chemical bonds are formed by carbon? Why?
What type of chemical bond is present in chlorine molecule? Explain your answer.
Why is graphite used for making dry cell electrodes but diamond is not?
Give the formula of the compound that would be formed by the combination of the following pair of elements:
K and H
An element A has 4 valence electrons in its atom whereas element B has only one valence electron in its atom. The compound formed by A and B does not conduct electricity. What is the nature of chemical bond in the compound formed? Give its electron-dot structure.
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.
Define a covalent bond.
Explain the following:
polar covalent compounds electricity.
Fill in the blank with correct word from the bracket.
Melting and boiling points of covalent compounds are generally ______ (low, high).
Fill in the blank from the choice given in bracket.
The compound that does not have a lone pair of electrons is ___________. (Water, Ammonia, carbon tetrachloride)
Acids dissolve in water and produce positively charged ions. Draw the structure of these positive ions.
State the type of bond formed when the combining atom has zero E.N. difference.
Name two compounds that are covalent when taken pure but produce ions when dissolved in water.
Name gas with a rotten egg smell.
Fill in the blank and rewrite the completed statement:
Covalent compounds are generally soluble in _________ solvents.
Name two carbon compounds used in day-to-day life.
______ is an example of a covalent compound having a high melting point.
Molecular reactions are ______ in the covalent compound.
