AlCl3 dimmerised to Al2Cl6 by 3C-4e bond bridge bond and Al2Cl6 is neither hypovalent nor hypovalent rather its octet is complete. Al2Cl6 contains six bond having two bridge bond(3c-4e) and four bond is (2C-2e).
We
will used MOT here it cannot act as Lewis acid due to
crowding in spite having vacant d orbital’s however AlCl3 act
as Lewis acid.
Hydrolysis is a chemical process in which a certain molecule is split into two parts by the addition of a molecule of water. One fragment of the parent molecule gains a hydrogen ion (H+) from the addition of water. The other group collects the remaining hydroxyl group(OH-) for examples :
(1) During hydrolysis of a covalent compound having non
metal central atom, if water molecule attack at central atom and hydrolysis
occurs at room temperature then oxy acid of the non metal will be formed, if
the central atom is in it one of the common oxidation state. Oxidation state of central atom of the oxy acid will be same as its in the given substrate,
However this rule is not applicable to XeF2, XeF4 and XeF3.
(2) hydrolysis reactions occur in non redox
reaction except XeF2 and XeF4 and mixed anhydride i.e. central atoms has its
uncommon oxidation state for examples;
(3) During hydrolysis, hybridization of central atom in
transition state and may or may not change.
(4) BF3, SiF4, CCl4,
SbCl3, and BiCl3 undergo partial hydrolysis even in
excess of water while PCl5, SF4, SeF6,IF7,
XeF6 H4P2O8, H2S2O8,P4O10
can undergo partial as well as complete hydrolysis by adjusting the amount
water.
(5) Rate of hydrolysis is directly proportional
to the positive (+) charge density at least electronegative atoms of substrate provided. And the least electronegative atom must contain vacant orbital and have no crowding.The order of rate of hydrolysis of some compounds are given
as;
PCl5(V) > SiCl4(IV) > AlCl3(III)
> MgCl2(II) > CCl4 (NO vacant orbital) > SF6
(Crowding)
Related Questions:
Question (1): Why aqueous
solution of AlCl3 is acidic in nature?
Question (2): What happen when
aq AlCl3 react with Acid or Base?
Question (3): Although
anhydrous aluminium chloride is covalent but its aqueous solution is ionic in
nature. Why?
Question (4): Arrange in
increasing order of extent of hydrolysis [ CCI4, MgCI2,
AICI3, PCl5, SiCI4].
Question (5): Although Sulphur
contain vacant d-orbital but SF6 does not undergo hydrolysis. Why?
Question (6): CCl4 can
not be hydrolysed but SiCl4 can be. Why?
Question (7): What are the
hydrolysis products of urea?
Question (8): Why SF6 is
inert where as SF4 is highly reactive towards H20?.
Question (9): Why SF6 behaves
inert towards hydrolysis?
Question (10): Why PCl3 hydrolysed
while NCl3 can not be hydrolysed?
Question (11): Why hydrolysis
of NCl3 gives NH4OH and HOCl, while PCl3 on hydrolysis gives H3PO3 and HCl?
I2Cl6 is the dimer of ICl3 which is dimerised through (3C-4e-) bridge bonds. And it shape is rectangular planer and all the iodine as well as chlorine atoms lies in same plane. And (I-Cl-I) bridge bond have sp3d2-sp3-sp3d2 hybridization.
