(a) what happens when
(i) Chlorine gas is passed though a hot concentrated solution of NaOH?
(ii) sulphure dioxide gas is passed through an aqueses solution of Fe (III) salt?
(b) Answer the following :
(i) what is the basicity of `H_(3) PO_(3)` and why?.
(ii) why does fluorine not pay the role of a central atom in interhalogen compounds ?
(iii) Why do noble gases have very low boiling points ?

Explanation

(a) (i) `3Cl_(2) + 6NaOH to NaCl + NaCl + NaCl O_(3) + 3H_(2)O`.
(ii) Fe (III) Salt it reduced to Fe (II Salt) `2Fe^(3+) + SO_(2) + 2H_(2)O to 2Fe^(2+) + SO_(2-)^(4) + 4H^(-)`
(b) (i) It has one P= O, one P- H and two P-OH bonds. Since it has tow P-OH bonds, so it has two ionisable H atoms. Therefore, it behaves as dibasic or diprotic.

(ii) Fluorine done not paly the role of a central atom in interhalogen compounds because it is more electronegative elements and cannot exhibit any poisitive oxidation state.
(iii) Noble gases have low boiling point because atoms are held logether by weak vander waals force. Hence their boiling point is low.