Give reason for :
(i) `SF_6` is kinetically an inert substance.
(ii) The N - O bond in `N0_(2)^-` is shorter than the N - O bond in `NO_(3)^-`.

Explanation

(i) `SF_6` is kinetically inert due to the reason that 6 flourne atoms protect the sulphur atom from attack by the reagents to such an extent that even hydrolysis do not occur.
(ii) In `NO_(2)^-` the average N-O bond order is 1.5 due to two resonating structures whereas in `NO_(3)^-` the average N-0 bond order is 1.33 due to 3 resonating stuctures. Higher the bond order, Shorter the bond length.