`a.`
`c.` Tetrachloroethene does not give the test for unsaturation , `i.e.,` it does not decolourise `Br_(2)` water solution. Explain why

Explanation

`a.`
`b.`
There are four chiral centrest centres and each of them shows various enentiomers also.

`(F), (G)` and `(H)` have four chiral centres , but `(I)` has only three chiral centres and each of them will show various enantiomers also.
`c.`
Because of the `-I` effect of four `Cl` atoms `(i.e.,` electron withdrawing nature of chlorine `)` , the electron density at the double bond is greatly reduced and an attack by electrophilic bromin `(Br^(o+))` does not occur. Hence, it does not show the test for unsaturation.
`d.`
`e.` There is one `(C=C)` bond with different groups on each `(C=C)` bond and one chiral centre at `C=12` . It shows four geometrical land optical isomers.

`f.` In non`-` polar solvents, the reaction proceeds through a briged cation such as brominimum ion and then `Br^(c-)` attacks the protonated complex from the opposite face resulting in trans `(` anti`-` addition `)`.

In the presence of aqueous acid, since `H_(2)O` is a good ion sovator, the protonated complex to the free `R^(o+)` that can now react with `Br^(c-)` from either face giving both syn`-` and anti `-` addition.