(a) Account for the following:
(i) Acidic character increases from $\mathrm{HF}$ to $\mathrm{HI}$.
(ii) There is large difference between the melting and boiling points of oxygen and sulphur.
(iii) Nitrogen does not form pentahalide.
(b) Draw the structures of the following:
(i) $\mathrm{C}∕{\mathrm{F}}_3$
(ii) ${\mathrm{XeF}}_4$
OR
(i) Which allotrope of phosphorus is more reactive and why?
(ii) How the supersonic jet aeroplanes are responsible for the depletion of ozone layers?
(iii) ${\mathrm{F}}_2$ has lower bond dissociation enthalpy than ${\mathrm{Cl}}_2$. Why?
(iv) Which noble gas is used in filling balloons for meteorological observations ?
(v) Complete the equation:
${\mathrm{XeF}}_2+{\mathrm{PF}}_5\mathrm{}\mathit{─}\mathit{─}\mathit{─}\mathit{─}▸$