Give reaasons :
a. `CCl_4` is used as a fire extinguisher but not `CS_(2)` ltbr. B. Sn is used to make solder .
c. The of lead pencil is not lead but greaphite .
d. despite the fact that carbon has only two unpaired elecrons . It is tretraveleant .
e.` CCl_(4)` does not act as Lewis acid , wille `SiCl_(4)` does ,

Explanation

a. `C Cl_4` is a geavy bon-combustible ilwuid , hence . It can be used as fire extinguisher.
On the other hand `CS_2` is a highly combustible gas and cannot be used to extinguish fire .
`2 CS_2 + 5O_2 rarr 2CO + 4 SO_2`
b. `Sn` is easily fusible alloying metal and hence is used in making solder .
c. Graphite has got the property of marking paper whereas lead does not have this propery . Hence the lead in lead pencil is graphite and not lead .
d. electronic configuration of carbon in the ground state is `2s^2 sp^2` i.e., it has only tow unpaired electrons . Despite this , carbon is always tetravalent , as the energy required for unpaireing and promting electron form `2s` orbital to `2p` orbital is more than compensated by the enrgy released when carbon forms four bonds e.g. `CX_4` type of compound . Hence carbnon si alwys tetravalent

e. `C` in `C Cl_4` does not have vacant d-orbital in its valence shell in which it can accept an eletron paire form other molecule // ion and hence `C Cl_4` has does act as Lewis acid whereas `Si` in ` SiCl_4` has cacant `3d-`orbital in its valence shell and it can expand its coordination numbr form ` 4` to `61`. Thus `SiCl_4` behaves as a Lewis acide .
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