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प्रश्न
The pencil leads are made of mainly:
(a) lithium
(b) charcoal
(c) lead
(d) graphite
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उत्तर
graphite
The pencil leads are mainly made of graphite.
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संबंधित प्रश्न
What type of bonds are present in Cl2 molecule? Draw their electron-dot structures.
Fill in the following blank with suitable word:
The general formula CnH2n for cycloalkanes is the same as that of ...........
Give one example, state what are covalent compounds?
Draw the electron-dot structure of N2 and state the type of bonding.
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.
Elements forming ionic compounds attain noble gas electronic configuration by either gaining or losing electrons from their valence shells. Explain giving reason why carbon cannot attain such a configuration in this manner to form its compounds. Name the type of bonds formed in ionic compounds and in the compounds formed by carbon. Also explain the reason why carbon compounds are generally poor conductors of electricity.
Molecular formula of Propane is C3H8 , write the structural formula of propane.
Explain the following:
Covalent compounds have low melting and boiling point.
Give reason as to why hydrogen chloride can be termed as a polar covalent compound.
An element L consists of molecules.
Why L is heated with iron metal, it forms a compound FeL. What chemical term would you use to describe the change undergone by L?
Explain the following:
Polar covalent compounds conduct electricity?
Name two compounds that are covalent when taken pure but produce ions when dissolved in water.
Write the molecular formula of the given compound.
Propylene
Complete the following activity.
Write the names of the hydrocarbons for the following structural formula.
(isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane)
| \[\begin{array}{cc} \phantom{..}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\ \phantom{..}|\phantom{....}|\phantom{....}|\\ \ce{H - C - C- C- H}\\ \phantom{.}|\phantom{....}|\phantom{....}|\\ \ce{H - C - H}\\ |\\\ce{H}\end{array}\] |
Complete the following activity.
Write the names of the hydrocarbons for the following structural formula.
(isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane)
 |
Considering MgCl2 as ionic compound and CH4 as covalent compound give any two differences between these two compounds.
Which of the following is the purest form of carbon?
Which of the following statements are usually correct for carbon compounds? These
- are good conductors of electricity
- are poor conductors of electricity
- have strong forces of attraction between their molecules
- do not have strong forces of attraction between their molecules.
Non-polar covalent compounds are ______ conductors of heat and electricity.
