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Stability of acetic acid and its conjugate base!

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Winga:
Acid-base reaction:

CH3COOH  +  H2O  <===>  CH3COO-  +  H3O+
___acid__________________conjugate base_______

I found 2 explanations about the shift of equilibrium.

1.
The pKa value of hydronium ion (H3O+) is -1.7, while acetic acid is 4.7.
H3O+ is more acidic than acetic acid, thus, the equilibrium is shift to left.

2.
By comparing the stability of acetic acid and acetate, because there is delocalization of electrons presented in acetate between O-C-O atoms, acetate gains extra stability, so, the equilibrium shifts to the side (right) with more stable product.

Are there any problems in these two explanations?

Thanks!

By the way, I have a question about comparing the stability of acetic acid and acetate. In acetate, because of delocalization of electrons, the -ve charge is being diminished by resonance effect. However, acetate is still got a -ve charge although it is smaller than 1.

On the other hand, acetic acid is neutral (no charge), so, is acetic acid more stable than acetate?

movies:
Acetic acid is more stable because it has more bonds.  I think that the take home message from your second explanation should be that the charge on an deprotonated carboxylic acid is more stable than, say, the charge on a deprotonated alcohol.  Your two explanations are somewhat conflicting, right?  There is some population of the right hand side of the equation, but the equilibrium is shifted mostly to the left by the reasoning in your first point.  The second point means that the right side of the equation is more accessible than it would be if there wasn't that stabilization of the negative charge.

I hope that makes sense.

Winga:
But, if I compare the stability of phenol and phenoxide, both have resonance effect, and phenoxide is more stable than phenol, because in phenol, energy is needed to separate unlike charges.

This time, which one is more stable, phenol and phenoxide?


By the way, why there is charges separation in phenol (I know the mechanism)? Unlike charges should be attracted together naturally, so, is resonance effect really existed in phenol?

movies:
Phenol is still more stable than phenoxide, again because there are more bonds.

Similar to the acetate case, the energies are brought closer together because in phenoxide the charge can be "smeared out" over the aromatic ring.  The resonance effect in phenol is smaller than in phenoxide because it requires a positive charge on the oxygen and a negative charge somewhere else in the ring.  That is what is meant by charge separation.  It takes energy to pull those charges apart since, as you stated, they would be attracted to one another.

Winga:
From this reaction:
CH3COOH  +  H2O  <=>  CH3COO-  +  H3O+

In this case, if I add much water into the system, will the equilibrium shifts to right hand side?

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