try..try,,,

Iso Electric point is the pH at which a particular molecule or surface carries no net electrical charge.

Let the conc of H+ = x
Let the conc of OH- = 10^-14/x

let the dissociation of x be α, of z be β. Then of Y will be α+β

10^-4.3=[H+][α]/[1-2α-2β]
10^-2.2=[H+][β]/[1-2α-2β]

10^-2.2+10^-4.3=[H+][α+β]/[1-2α-2β]

10^-14/10^-9.7=[α+β]/[1-2α-2β] 10^-14/[H+]
[H+]/10^-9.7=[α+β]/[1-2α-2β]

Eliminate

10^-2.2+10^-4.3=[H+][H+]/

10^-9.7(10^-2.2+10^-4.3)=[H+][H+]

you get [H+]=5.95

See if this is the right answer...

for no net charge...

because if X dissociates by α.. then there is a -ve charge created

same with Z due to dissociation by beta

So for total net neutral charge the ionisation of Y should be α+beta

See if this logic is right

you guys anyway know how good my chemistry is :D

yes exactly..

so the net charge has to be zero.. is that only possible if amount of decrease is equal to amount of increase?

I saw that post...

basically if there is a solution.. then you have equilibrium constants..

the total charge will not depend on where you start with!!

will it?

Even there I think you have to consider the equilibrium of NH3+ species at that pH.

I think sky has ignored that altogether.... !!

I saw that post soon after posting the solution to this one....

in that question..

pKa2 is the equilibrium constant of some other reaction.. between two species...

But then I am not very sure.. you know how good I am at chemistry..

abhee Ihave to go.. when I come back i will think more on this one..

by that time, manish is trying this one :)

well the proof of this is given in the link that priyam posted.. but i did not understand it!!

you can read the proof and explanatin there :)

Yeah answer will be (pK1+pK2)/2

As the molecule required is HOOCCH₂CH(NH₃⁺)COO^-

which is between HOOCCH₂CH(NH₃⁺)COOH and ^-OOCCH₂CH(NH₃⁺)COO^-

so no K_a3 is required