question_answer 1)

  Give reasons for the following : (a) \[CC{{l}_{4}}\] is immiscible in water whereas \[SiC{{l}_{4}}\] is easily hydrolysed. (b) Carbon has a strong tendency for catenation compared to silicon.

Answer:

  (a)\[CC{{l}_{4}}\]is immiscible in water as it is a covalent compound and is not hydrolysed by water because carbon does not have d-orbitals and hence cannot expand its coordination number beyond 4. However, silicon can expand its coordination number beyond 4 due to availability of d-orbitals.                                 \[CC{{l}_{4}}+{{H}_{2}}O\xrightarrow{{}}No\,reaction\]                                 \[SiC{{l}_{4}}+4{{H}_{2}}O\xrightarrow{{}}Si{{(OH)}_{4}}+4HCl\] (b) The property of catenation depends upon the strength of element-element bond. Since, the bond energy of C-C bond is very large\[(348kJ\,mo{{l}^{-1}})\], carbon has strong tendency of catenation, while the bond energy of Si-Si bond is comparatively less \[(297\,kJmo{{l}^{-1}})\]and it has lesser property of catenation.