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प्रश्न
Explain the following:
Why does the element silicon, not form a graphite like structure whereas carbon does.
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उत्तर
In graphite, carbon is sp2-hybridised and each carbon is linked to three other carbon atoms by forming hexagonal rings. Each carbon is now left with one unhybridised p-orbital which undergoes sideways overlap to form three p-p double bonds. Thus, graphite has two-dimensional sheet like (layered) structure consisting of a number of benzene rings fused together. Silicon, on the other hand, does not form an analogue of carbon because of the following reason:
Due to bigger size and smaller electronegativity of Si than C, it does not undergo sp2-hybridisation and hence it does not form p-p double bonds needed for graphite like structure. Instead, it prefers to undergo only sp3-hybridisation and hence silicon has diamond like threedimensional network
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संबंधित प्रश्न
Rationalise the given statement and give a chemical reaction:
Lead (II) chloride reacts with Cl2 to give PbCl4.
Explain why is there a phenomenal decrease in ionisation enthalpy from carbon to silicon?
Classify the following oxide as neutral, acidic, basic or amphoteric:
CO2
Classify the following oxide as neutral, acidic, basic or amphoteric:
Al2O3
Write suitable chemical equations to show the nature of the following oxide.
SiO2
Write suitable chemical equations to show the nature of the following oxide.
Al2O3
Write suitable chemical equations to show the nature of the following oxide.
PbO2
The reason for small radius of Ga compared to Al is:
(i) poor screening effect of d and f orbitals.
(ii) increase in nuclear charge.
(iii) presence of higher orbitals.
(iv) higher atomic number.
Give reasons for the following:
CCl4 is immiscible in water, whereas SiCl4 is easily hydrolysed.
Explain the following:
CO2 is a gas whereas SiO2 is a solid.
Explain the following:
Silicon forms \[\ce{SiF^{2-}6}\] ion whereas corresponding fluoro compound of carbon is not known.
Carbon and silicon both belong to the group 14, but inspite of the stoichiometric similarity, the dioxides, (i.e., carbon dioxide and silicon dioxide), differ in their structures. Comment.
Explain the following:
Carbon shows catenation property but lead does not.
Explain the following:
BF3 does not hydrolyse.
A tetravalent element forms monoxide and dioxide with oxygen. When air is passed over heated element (1273 K), producer gas is obtained. Monoxide of the element is a powerful reducing agent and reduces ferric oxide to iron. Identify the element and write formulas of its monoxide and dioxide. Write chemical equations for the formation of producer gas and reduction of ferric oxide with the monoxide.
\[\ce{SiCl4 ->[H2O] (A) ->[\Delta] (B) ->[Na2CO3][heat] (C)}\]. The Compound C is ______.
Which one of the following compounds of Group–14 elements is not known?
Match List I with List II:
| List I | List II |
| Coke | Carbon atoms are sp3 hybridized. |
| Diamond | Used as a dry lubricant. |
| Fullerene | Used as a reducing agent. |
| Graphite | Cage like molecules |
Choose the correct answer from the options given below:
