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प्रश्न
Why is diamond used for making cutting tools (like glass cutters) but graphite is not?
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उत्तर
Diamond is the hardest, naturally occuring material known. Owing to its rigid structure, it can be used as glass cutters. Whereas graphite is a layered structure of carbon atoms and is very soft so, it cannot be used for making cutting tools.
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संबंधित प्रश्न
What are covalent compounds?
What type of bond exist in CCl4?
The number of isomers formed by the hydrocarbon with molecular formula C5H12 is:
(a) 2
(b) 5
(c) 3
(d) 4
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.
Give the formulae of the chlorides of the elements X and Y having atomic numbers of 3 and 6 respectively. Will the properties of the two chlorides be similar or different? Explain your answer.
Define a covalent bond.
For each compound mentioned above give the formulae of ions formed in aqueous solution.
Complete the following:
When the nuclei of two different reacting atoms are of ______ mass, then a bond so formed is called ______ covalent bond. (equal, unequal, polar, non-polar)
Distinguish between ionic and covalent compounds under the following properties:
(i) Strength of forces between constituent elements
(ii) Solubility of compounds in water
(iii) Electrical conduction in substances
Write answer as directed.
What causes the existance of very large number of carbon compound ?
Molecular formula of Propane is C3H8 , write the structural formula of propane.
Give examples for the following:
Two gaseous non polar compounds.
Acids dissolve in water to produce positively charged ions. Draw the structure of these positive ions.
Compound X consists of molecules.
Choose the letter corresponding to the correct answer from the options A, B, C and D given below:
The type of bonding in X will be ______.
Identify the incorrect statement and correct them.
- Like covalent compounds, coordinate compounds also contain charged particles (ions). So they are good conductors of electricity.
- Ionic bond is a weak bond when compared to Hydrogen bond.
- Ionic or electrovalent bonds are formed by mutual sharing of electrons between atoms.
- Loss of electrons is called Oxidation and gain of electron is called Reduction.
- The electrons which are not involved in bonding are called valence electrons.
Consider the coordination compound, K2[Cu(CN)4]. A coordinate covalent bond exists between:
Two carbon atoms can always form one or two covalent bonds.
`"CH"_3 - "CH"_2 - "OH" overset("Alkaline""KMnO"_4 + "Heat")(->) "CH"_3 - "COOH"`
In the above given reaction, alkaline KMnO4 acts as
The table shows the electronic structures of four elements.
| Element | Electronic Structure |
| P | 2, 6 |
| Q | 2, 8, 1 |
| R | 2, 8, 7 |
| S | 2, 8, 8 |
- Identify which element(s) will form covalent bonds with carbon.
- “Carbon reacts with an element in the above table to form several compounds.” Give suitable reason.
Molecular reactions are ______ in the covalent compound.
