When a soluble aluminium salt is placed in water at room temperature. Initially the aluminium ion is surrounded by six water molecules and the complex ion has the predicted octahedral Geometry.
These equilibria give rise to an acidic solution in water, to the Hexahydroxoaluminate(iii) ion [Al(OH)6]3- in a strongly alkaline solution, and only in strongly acidic solutions is the hexaaquo ion [Al(H2O)6]3+ found.
The solid
hydrate, often written AlCl3. 6H2O and more correctly [Al(H2O)6]Cl3 can, therefore,
only be obtained from a strongly acidic solution. The reaction with water
resulting in the liberation of a proton is again known as hydrolysis and occurs whenever the
central metal ion is small and highly charged (i.e. having a high surface
density of charge), for example in salts of iron(III), chrornium(III).
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 ?
(4) What is structure of solid Ortho Boric acid ?
(5) What is the structure of trimetaboric acid and trimetaborate ion?
(6) Why Borazine is more reactive than benzene towards Electrophic Aromatic substitution reactions ?
(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?
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