Question

Maximum efficiency of cation hydrolysis will be shown by?
a) \(\sf Al^{+3}\)
b) \(\sf Tl^{+3}\)
c) \(\sf Tl^{+1}\)
d) \(\sf Ga^{+3}\)

Answer 1

The answer is \(\sf Al^{+3}\) but how?

Answer 2

@chmvijay

Answer 3

@Woodward !!!!!
Any Idea?

Answer 4

Hmmm well I don't really know what cation hydrolysis is, I am guessing it has to do with somehow breaking a bond and acting as a catalyst to allow water to join in to break the bond. But past that, I don't really have much of an idea other than I know aluminum has a smaller ionic radii, thus higher charge density than the other metals. I see that all of these are in the same column of the periodic table, so I'm sure there's some trend we should be aware of here but I have no idea what's really happening here.

Answer 5

Tell me whatever you know or think about this, maybe we can figure it out, I tried googling this but nothing really came up so I couldn't find anything about this unfortunately! Send me some links or explain some more of this so I can try to learn!

Answer 6

one min

Answer 7

Ok, so this is basically related with salt hydrolysis in aqueous solution.
E.g. if we dissolve a acidic salt BA in water then following can be written,

\(\sf BA + H_2O <---> BOH + HA\\or ~B^++A^-+H_2O <---> BOH+H^++A^-\\or~B^++H_2O <---> BOH+H^+\)

Answer 8

Note, BOH doesn't dissociates because it's weak. This is called cation Hydrolysis. I don't know about how to determine efficiency....

Answer 9

Looks like hydrolysis is related with cation size....

Answer 10

According to one of my books, Hydration Energy \(\propto \)Catonic charge\(\propto\)1/cationic size

Answer 11

Can I say that more the hydration energy more will be efficiency of hydrolysis?

Answer 12

I'm reading this: http://www.chemguide.co.uk/physical/energetics/solution.html

but I am not sure this applies. I'm still not sure I understand what cation hydrolysis is. "Note, BOH doesn't dissociates because it's weak. This is called cation Hydrolysis" Could you explain this more?

I also am not really sure what they mean by efficiency, like does it dissociate/cause a bond to break more? Hmm

Answer 13

Since, BOH is weak acid its degree of dissociation is very small (<<1), that's why it is fair enough to say that BOH formed after hydrolysis remains in undissociated state and that's why the resulting aqueous solution is acidic in nature. If it where some salt of strong acid and strong base, both the acid and base formed after hydrolysis would have equally dissociated and equal amounts of H+ and OH- ions would have been formed and pH of the solution would have been 7

Answer 14

Umm.. I think efficiency of hydrolysis is related with hydration energy. More the hydration energy greater will be the efficiency and hydration energy is in turn directly proportional to the cationic/anionic charge and inversely proportional to cationic/anionic radius.

Answer 15

That explains why Al+3 has greatest efficiency....

Answer 16

Oh, is that the correct answer? :O

Answer 17

Yes!!