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प्रश्न
An element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following
पर्याय
Mg
Na
P
Ca
उत्तर
Na
Explanation -
Sodium is a third-period alkali metal which is a soft metal and highly reactive. sodium is stored under kerosene and whenever it comes in contact with air or water it reacts vigorously.
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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?
How does graphite act as a lubricant?
What type of bonds are present in CO2 molecule? Draw their electron-dot structures.
Which inert gas does the Cl atom in HCl resemble in electron arrangement?
State one use of diamond which depends on its 'extraordinary brilliance' and one use of graphite which depends on its being 'black and quite soft'.
Two non-metals combine with each other by the sharing of electrons to form a compound X.
(a) What type of chemical bond is present in X?
(b) State whether X will have a high melting point or low melting point.
(c) Will it be a good conductor of electricity or not?
(d) Will it dissolve in an organic solvent or not?
Draw an electron dot structure of the following molecule. (Without showing the circle) :
Methane
(a) Compound X consists of molecules.
Choose the letter corresponding to the correct answer from the choices (a), (b), (c) and (d) given below
X is likely to have a :
Fill in the blank with correct word from the bracket.
Melting and boiling points of covalent compounds are generally ______ (low, high).
Draw the electron dot diagram and structure of :
methane
Name two carbon compounds used in day-to-day life.
The number of electrons in the valence shell of a carbon atom is 4.
Write an Explanation.
Alkyne
Write a short note.
Aromatic hydrocarbons
Complete the following activity.
Write the names of the hydrocarbons for the following structural formula.
(isobutylene, cyclohexane, propene, cyclohexene, cyclopentane, benzene, propyne, isobutane, propane)
| \[\begin{array}{cc}\phantom{......}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{..}\\ \phantom{.....}|\phantom{....}|\phantom{....}|\\ \ce{H - C - C = C}\\\phantom{.....}|\phantom{.........}|\\ \phantom{.....}\ce{H}\phantom{........}\ce{H}\end{array}\] |
Which of the following are correct structural isomers of butane?
- \[\begin{array}{cc}
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\phantom{....}|\phantom{....}|\\
\ce{H - C - C - C - C - H}\\
|\phantom{....}|\phantom{....}|\phantom{....}|\\
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
\end{array}\] - \[\begin{array}{cc}
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\phantom{....}|\\
\ce{H - C - C - C - H}\\
|\phantom{.....}|\phantom{.....}|\\
\ce{H}\ce{H-C-H}\ce{H}\\
|\\
\ce{H}\\
\end{array}\] - \[\begin{array}{cc}
\ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\phantom{....}|\\
\ce{H - C - C - C - H}\\
|\phantom{.....}\backslash\phantom{..}|\\
\phantom{....}\ce{H}\phantom{......}\ce{C - H}\phantom{}\\
\phantom{.......}|\\
\phantom{.......}\ce{H}\\
\end{array}\] - \[\begin{array}{cc}
\ce{H}\phantom{...}\ce{H}\\
|\phantom{....}|\\
\ce{H - C - C - H}\\
|\phantom{....}|\\
\ce{H - C - C - H}\\
|\phantom{....}|\\
\ce{H}\phantom{...}\ce{H}\\
\end{array}\]
"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.
Assertion (A): Melting point and boiling point of ethanol are lower than that of sodium chloride.
Reason (R): The forces of attraction between the molecules of ionic compounds are very strong.
