Long Answer TypeWhat do you understand by (a) inert pair effect (b) allotropy and (c) catenation?
Inert pair effect: As one moves down the group, the tendency of s-block electrons to participate in chemical bonding decreases. this effect is known as inert pair effect. In case of group 15 elements, the electronic configuration is ns2 np3 .Group 15 elements also show positive oxidation states of +3 & +5 by forming covalent bonds. Due to the inert pair effect, the stability of +5 oxidation state decreases down the group, while that of +3 oxidation state increases. This happens because of the poor shielding of ns2 electrons by the d- and f- electrons.
allotropy: allotropy is the existence of an element in more than one form, having the same chemical properties but different physical properties. the various forms of an element are called allotropes. For example, carbon exist in three allotropic forms such as diamond. graphite and fullerenes.
Catenation: carbon atoms can link with one another by means of covalent bonds to form a long chain or rings of carbon atoms. This property of carbon element due to which its atoms can join with one another to form a long chain is called catenation. It is most common in carbon and quite significant in Si and S.
Multiple Choice QuestionsSilicon oil is obtained from the hydrolysis and polymerisation of
trimetylchlorosilane and dimethyldichlorosilane
trimethylchlorosilane and methyldichlorosilane
methyltrichlorosilane and dimethyldichlorosilane
triethylchlorosilane and dimethyldichlorosilane
The orange solid on heating gives a colourless gas and a green solid which can be reduced to metal by aluminium powder. The orange and the green solids are, respectively
NH4Cr2O7 and Cr2O3
Na2Cr2O7 and Cr2O3
K2Cr2O7 and CrO3
(NH4)2CrO4 and CrO3
Match the following.
| List I | List II | ||
| (A) | Flespar | (I) | [Ag3SbS3] |
| (B) | Asbestos | (II) | Al2O3.H2O |
| (C) | Pyrargyrite | (III) | MgSO4.H2O |
| (D) | Diaspore | (IV) | KAlSi3O8 |
| (V) | CaMg3(SiO3)4 |
(A) (B) (C) (D)
IV V II I
(A) (B) (C) (D)
IV V I II
(A) (B) (C) (D)
IV I III II
(A) (B) (C) (D)
II V IV I
Diamond is hard because
all the four valence electrons are bonded to each carbon atoms by covalent bonds
it is a giant molecule
it is made up of carbon atoms
it cannot be burnt
Monosilane on coming in contact with air bums with a luminous flame producing vortex rings. These rings are of
SiO2
SiO
Si
H2SiO3
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