a. Select the member `s` of grop `14` that (i) forms the most acidic diozide (ii) is commonly found in `+2` oxidation state and (iii) used as se,ocpmdictpr .
(Solved NCEGT Pronlem `11.5`)
b. `|SiF_5^(2-) ` is known, whereas `|SiCl_5|^(2-)` not. Glve possible preasons .
(Solved NCEGT Pronlem `11.6`)
c . Diamond is covalent , yet covelnt , yet it has high melting point . Why ?
(Solved NCEGT Pronlem `11.7`) .

Explanation

i. Carbon
ii. Lead
iii. Silicon and germanium
b. `[SiF_(6)]^(2-)` is knon, wheras `[SiCl_(6)]^(2-)` is not . This is because
`F` is smaller in size as compared to `Cl` , so six flourine atoms can be easily accommodated aroune `Si` atom but six size `Cl` atoms cannot be accommodates areoun d `Si` due to steric hinderance .
ii. The interaction between an electron paire present in `2p`-orbital on `F` and vacant `3d` orbital is stronger resulting in `p` pi-d pui ond formation m which is not so effective between large `3p` orbital of `cl` and `3d` orbital so `Si`.
.
e. Diamond has a three-dimensional network involving srong `C-C` bonds , which are very difficult to break. and thus diamond has high melting pointy .