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transition metals (a level chemistry)(help me)

When [Al(H20)6]3+ reacts with Na2CO3, it forms Al(H20)3(OH)3

But when [Cu(H20)6]2+ reacts with Na2CO3, it forms CuCO3 despite the conditions being the same

Why is this the case?
Reply 1
The charge on the transition metal ion affects its acidity, and that determines what products you get.
3+ ions are sufficiently acidic to form the metal hydroxide ppt.
2+ ions are not as acidic and form the metal carbonate ppt.

There's a nice explanation here:

As for why there is a difference in acidity, it's due to the charge density on the metal ion and how that affects the strength of the O-H bonds in its water ligands

Again there's a nice explanation here:
aluminium is amphoteric. this means it has the ability to act as both an acid and a base. in this case, it is acting as an acid because it is donating 3 protons, to gain a neutral charge. the second reaction is a displacement reaction, and it is with copper which isnt amphoteric

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