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प्रश्न
What is diamond? Of what substance is diamond made?
उत्तर
Diamond, which is a colourless and transparent substance, is an allotrope of carbon. It is the hardest natural substance known. Diamonds are purely made of carbon and the symbol is C. When we burn diamond in oxygen, only carbon dioxide is evolved showing that diamond is made up of carbon.
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संबंधित प्रश्न
Choose the correct answer from the options given below:
Which of the following is a common characteristic of a covalent compound?
1) high melting point
2) consists of molecules
3) always soluble in water
4) Conducts electricity when it is in the molten state
Why are most carbon compounds poor conductors of electricity?
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?
What type of bonds are present in hydrogen chloride and oxygen?
Fill in the blank in the following sentence:
Two chlorine atoms combine to form a molecule. The bond between them is known as ..........
Fill in the blank in the following sentence:
The number of single covalent bonds in C2H2 molecule are ...........
Draw the electron-dot structure of HCl compound and state the type of bonding.
Out of KCl, HCl, CCl4 and NaCl, the compounds which are not ionic are:
(a) KCl and HCl
(b) HCl and CCl4
(c) CCl4 and NaCl
(d) KCl and CCl4
The number of covalent bonds in pentane (molecular formula C5H12) is:
An element E exists in three allotropic forms A, B and C. In allotrope A, the atoms of element E are joined to form spherical molecules. In allotrope B, each atom of element E is surrounded by three other E atoms to form a sheet like structure. In allotrope C, each atom of element E is surrounded by four other E atoms to form a rigid structure.
(a) Name the element E.
(b) What is allotrope A.
(c) What is allotrope B?
(d) What is allotrope C?
(e) Which allotrope is used in making jewellery?
(f) Which allotrope is used in making anode of a dry cell?
What happens when methane (natural gas) burns in air? Write the chemical equation of the reaction involved.
State the type of bonding in the following molecule.
Hydroxyl ion
Draw an electron dot structure of the following molecule. (Without showing the circle) :
Methanol
Give examples for the following:
Two gaseous non polar compounds.
Explain the following:
Covalent compounds have low melting and boiling point.
Elements Q and S react together to form an ionic compound. Under normal conditions, which physical state will the compound QS exist in?
Write an Explanation.
Alkene
Complete the following activity.
Write the names of the hydrocarbons for the following structural formula.
(isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane)
| \[\begin{array}{cc}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\ |\phantom{....}|\phantom{....}|\\\ce{H - C - C - C - H}\\ |\phantom{....}|\phantom{....}|\\\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H} \end{array}\] |
Give an example for each of the following statement.
Formation of coordinate covalent bond between NH3 ➝ BF3 molecules
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.
