The Student Room Group

Transition metal reactions summary sheet????

Hey!! is anyone else doing AQA A-level chemistry? if so, do you know of any good summary sheets of the transition metal reactions with Ammonia, water, carbonate ions, and alkalis, (NaOH) some of the stuff in our text books is a little contradictory!
for example, can anyone tell me whether metal (3) ions (AlCl3) actually hydrolyse when only added to water? in the chapter on inorganic ions it says that it doesn't:
AlCl3 + excess H2O ---> (Al(H2O)6)3+ +3Cl
but in the chapter on periodicity, it says that it does, but only slightly! not to the neutral ppt!!:
AlCl3 ---> Al3+ + 3Cl-
then just that the hydrated Al3+ ion is only partly hydrolysed!!
(Al(H20)6)3+ ---> (Al(H2O)5 OH) +H


is that it tho?? or is it just that theyv not completed the stages of the reactions in the first one?? wouldnt the hexa aqua aluminium ion then go on to be hydrolysed to the neutral precipitate (Al(H2O)3 OH3)??? but then why doesnt the second reaction go to completion as well!!! it might be that theyre just demonstrating the varying hydrolysing powers of the period 3 elements in the periodicity chapter???? but i have no idea!!!! someone please help!!! :confused: :smile:
Reply 1
have a look at this website, might help you a bit!

http://users.argonet.co.uk/users/hoptonj/assets/A5TM2.PDF
Reply 2
cool!! thanks!!!!
Reply 3
Emma18

for example, can anyone tell me whether metal (3) ions (AlCl3) actually hydrolyse when only added to water? in the chapter on inorganic ions it says that it doesn't:
AlCl3 + excess H2O ---> (Al(H2O)6)3+ +3Cl
but in the chapter on periodicity, it says that it does, but only slightly! not to the neutral ppt!!:
AlCl3 ---> Al3+ + 3Cl-
then just that the hydrated Al3+ ion is only partly hydrolysed!!
(Al(H20)6)3+ ---> (Al(H2O)5 OH) +H
:confused: :smile:


this is one of those reactions where excess (loads) of water is different from adding minute increments of water.

With the large amount of water, there is only one reaction (ALCL3 + H20----> ALCl2(OH) + H30+)

whereas with small amounts of water you get a progresion where every cl is replaced with OH- so you eventually get AL(OH)3. If you know someone whos got the NAS book (Making the Grade) use that it is amazing, but only for the edexcel syllabus (so not worth buying for the other topics)