InterviewSolution
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InterviewSolution
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Select the false statements from the following and try to justify your assertion: (a) Like carbon, silicon also existas in the free state. (b) `B(OH)_(3)` is acidic in nature. (c) Boron dissovles in hydrochloric acid. (d) The composition of common glass is `Na_(2)O,CaO.6SiO_(2)`. (e) Silica contains `SiO_(2)` molecules with O=Si=O bonds. (f) `BF_(3)` is a strnger Lewis acid than `BCl_(3)` (f) Water glass is sodium silicate. (h) diborane cannot have ethane like structure because it is not a covalent molecule. |
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Answer» (a) Silicon does not exist in free state becaue it is more reactive than carbon due to bigger size andalso lesser ionisation enthalpy. (c) Boron dissolves only in oxidising acids like `H_(2)SO_(4)` and `HNO_(3)` to form boric acid. As HCl is not strong oxidising agent, boron does not dissolve in HCl. (e) In silica O=Si=O cannot be present due to the different in the energy state of 2p orbital of oxygen and 3p orbial of silicon which are to participitate in sidewise overlapping. (f) `BF_(3)` is a weaker Lewis acid than `BCl_(3)` because of greater magnitude of `p pi- p pi` back bonding, resulting in more electron density on the boron atom. (h) dibronae cannot have a ethane like structure becasue boron atom is trivalent and more than three hydrogen atoms cannot be linked to it. thus `H_(3)B-BH_(3)` structure is not possible in this case. |
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