(i) What happens when
(a) Chlorine gas reacts with cold and dilute solution of NaOH?
(b) `XeF_(2)` undergoes hydrolysis ?
(ii) Assign suitable reasons for the following :
(a) `SF_6` is inert towards hydrolysis.
(b) `H_3PO_3` is diprotic.
(c) Out of noble gases only Xenon is known to form established chemical compounds.

Explanation

(i) (a) Chlorine gas with cold dilute NaOH
`2NaOH+Cl_2to NaCl +NaOCI+H_2O`
(b) `XeF_2` udnergoes hydrolysis
`2XeF_2+2H_2Oto O_2+2Xe+4HF`
(ii)(a) In `SF_6`' six atoms of flourine sterically protect the sulphur atom from the attack by the reagents to such an extent that even theromodynammically most favourable raction like hydrolysis do not occur. Hence `SF_6` is chemically inert.
(b) `H_3PO_3` is diprotic because it has only two OH groups and therefore give only two ionisable `H^(+)` ions in aqueous solution.

(c) Xenon has least ionisation enthalpy among noble gas, thus it forms chemical compounds with flourine and oxygen (which are highly electronegative and small sized atoms) readily only under certain conditions.