State reasons for each of the following :
(i) All the P-Cl bonds in molecule are not equivalent.
(ii) Sulphur has greater tendency for catenation than oxygen.
(i)The molecule has hybridization and trigonal bipyramidal geometry. Therefore it has 3 equatorial P-Cl bonds and two axial P-Cl bonds. Since two axial P-Cl bonds are repelled by 3 bond pairs while 3 equatorial bonds are repelled by two bond pairs, so axial bonds are longer than equatorial bonds.
(ii) The greater catenation tendency of sulphur is due to two reasons :
(a) The lone pair of electrons feels more repulsion in O-O bond than S-S bond due to its small size and thus S-S forms strong bond.
(b) As the size of atom increases down the group from O-PO, the strength of bond increases and therefore catenation tendency also increases.