[NewtoAtoms]

Hello Organic Chemists,

Which of the following species is NOT an intermediate in the generally accepted mechanism for the reaction shown:

I have done my research though all my reactions and here's what I know:

This is an ester hydrolysis reaction in an acidic aqueous solution.

1.  OKAY this is an acceptable intermediate (step #4 during which the alcohol is lost)
2.  OKAY this is an acceptable intermediate (step #4 immediate before #1)
3.  Hum... got me stumped (this could be possible as H leaves before joining alcohol which soon detaches)
4.  Hum... other one I am contemplating (I think this is impossible, as there is never 2 H gone at once)
5.  Okay this is an acceptable intermediate (step #3 before transfer of proton)

Can anyone shed some light on my perplexing choice between picture #3 and #4

I am grateful for your time.

[aldoxime_amine]

3.  Hum... got me stumped (this could be possible as H leaves before joining alcohol which soon detaches)
5.  Okay this is an acceptable intermediate (step #3 before transfer of proton)

Transfer of the above mentioned proton is not through solvent.

4.  Hum... other one I am contemplating (I think this is impossible, as there is never 2 H gone at once)

So the answer would seem to be this.

[azmanam]

you'll never have a negative charge on a major organic intermediate in an acidic mechanism.

Likewise, you'll never have a positive charge in a basic mechanism.

[NewtoAtoms]

a great, learned something new!!!

Thank you chemists!