Which is the correct sequence in the following properties? For the correct order mark (T) and for th — p Block Elements Chemistry Question
Question
Which is the correct sequence in the following properties? For the correct order mark (T) and for the incorrect order mark (F):<br>(a) Lewis acidity order : SiF4 < SiCl4 < SiBr4 < SiI4<br>(b) Melting point : NH3 > SbH3 > AsH3 > PH3<br>(c) Boiling point : NH3 > SbH3 > AsH3 > PH3<br>(d) Dipole moment order : NH3 > SbH3 > AsH3 > PH3
💡 Solution & Explanation
(a) (F); As the size of halogen atom increases crowding on Si atom will increase, hence, tendency of attack of Lewise base decreases.<br>(b) (T); M.P. of NH3 is highest due to intermolecular H-bonding in it. Next lower M.P. will be of SbH3 followed by AsH3 due to high mol. wt. of SbH3.<br>(c) (F); M.P. and B.P. of increase from PH3 to SbH3 via AsH3 due to increase in mol. wt. NH3 does not follow this trend due to inter molecular H-bonding. Increasing B.P. order : PH3 < AsH3 < NH3 < SbH3<br>(d) (T); Value of bond moment decreases.