Which is the correct sequence in the following properties? For the correct order mark (T) and for the incorrect order mark (F):(a) Lewis acidity order : SiF4 < SiCl4 < SiBr4 < SiI4(b) Melting point : NH3 > SbH3 > AsH3 > PH3(c) Boiling point : NH3 > SbH3 > AsH3 >PH3(d) Bond dipole order : NH3 > SbH3 > AsH3 > PH3

(a) (F) As the size of halogen atoms increases, crowding on Si atom will increase, hence tendency of attack of Lewis base decreases.(b) (T) M.Pt. of NH, is higher due to H-bonding.(c) (F) M.Pt. and B.Pt increases from PH3 to SbH3 due to increase in molecular mass, but NH3 is exception (due to H-bonding) B.Pt. order : SbH3 > NH3 > AsH3 > PH3(d) (T)