(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) F2 has lower bond dissociation enthalpy than Cl2. Why?
(iv) Which noble gas is used in filling balloons for meteorological observations?
(v) Complete the equation: XeF2 + PF5 →
i) White phosphorus is most reactive of all the allotropes of phosphorus because it is unstable due to the angular strain on P4 molecule with the bond angle of 60°.
(ii) Nitrogen oxide emitted from the exhausts of supersonic jet aeroplanes readily combine with ozone to form nitrogen dioxide and diatomic oxygen.
NO(g) + O3(g) →NO2(g) +O2(g)
Since supersonic jets fly in the stratosphere near the ozone layer, they are responsible for the depletion of ozone layer.
(iii) The size of a fluorine atom is very small as compared to a chlorine atom. Therefore, the repulsion between electrons in the outer most shell of the two atoms in a fluorine molecule is much greater than that in a chlorine molecule. Hence, it requires less energy to break up the fluorine molecule, making its bond dissociation energy lesser than that of chlorine molecule.
(iv) Helium, being light, non-inflammable and unreactive, is used for filling of balloons for metrological observations.
(v) XeF2 + PF5→ [XF]++[PF6]-
