Assign a reason for each of the following :
(I) `SCl_(6)` is not known but `SF_(6)` is known.
(ii) Sulpher hexafluoride is used as a gaseous electrical insulater.

Explanation

(i) Fluorine is much stronger oxidizing agent than chlorine, therefore, it can easily oxidise sulphur to its maximum oxidation state of `+6` and hence forms `SF_(6)`. Chlorine, on the other hand, being a weaker oxidizing agent can oxidise sulphur at the maximum to its `+4` oxidation state and hence can form `SCI_(4)` but not `SCl_(6)`. (ii) `SF_(6)` is a colourless, odourless and non-toxic gas at room temperature. It is thermally stable and chemically inert. Because of its inertless and high tendeny to suppress internal discharges, it is used as a gaseous electrical insulater in high voltage generatros and switch gears.