Although anhydrous aluminium chloride is covalent but its aqueous solution is ionic in nature. Why?

Aluminium forms covalent compound with chloride because lonisation enthalpy (∆iH= +5137 kJ/mole) of Aluminium is very high due to small size and chlorine is unable to convert  Al into Al⁺³ ions. 

However, when anhydrous AlCl₃ (which is covalent in character) is dissolved in water, it undergoes hydration as follow:  

 Al₂CI₆ + H₂O --> 2[Al(H₂O)₆]⁺³ + (∆H)  

Hydration of anhydrous aIuminium chloride is highly exothermic in nature. The hydration enthalpy is more than ionisation enthalpy of aluminium.This hydration enthalpy removes all the three valence electrons of the aluminium leading to the formation of Al³⁺ more easly.This AI³⁺ is hydrated with water and form a complex ion. Thus in water Al exist as [Al(H₂O)₆]⁺³ . The three electrons of aluminum is accepted by CI of AlCl₃. Thus hydrated AlCl₃  represented [Al(H₂O)₆]Cl₃   and it is ionic in nature.

Related Questions: 

(1) Although anhydrous aluminium chloride is covalent but its aqueous solution is ionic in nature. Why?

(2) Why Ga has small size than Al exceptionally

(3) Why aqueous solution of borax reacts with two moles of acids ?

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(5) What is the structure of trimetaboric acid and trimetaborate ion?  

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(7) Why Borazine (B3N3H6) is also known as inorganic benzene ?.

(8) Why B-F bond length in BF3 is shorter (130 pm) than B-F bond Iength in BF4- (143 pm)?. Explain.

(9) Why B-F do not exist as dimer?. Explain.

(10) Although anhydrous aluminium chloride is covalent but its aqueous solution is ionic in nature. Why?

(11) Why Boric acid become strong acid in the presence of cis 1,2-diol or 1,3-diol ?

(12) Four-center two-electron bond (4C-2e Bond): Structure of AlCl3:

(13) What is the molecular formula of Borax ?

(14) What is the difference between the structure of AlCl3 and diborane?