Medikj
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Is it correct to state that at 25°C, if any acid or base dissociates in water, than the amounts of each resulting ion specie is equal?
For instance,
If occurs CH3COOH <—> CH3COO- + H+ at 25°C
Then, [CH3COO-]=[H+]?
Is this valid at any temperature?

Thank you!
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Pigster
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(Original post by Medikj)
Is it correct to state that at 25°C, if any acid or base dissociates in water, than the amounts of each resulting ion specie is equal?
For instance,
If occurs CH3COOH <—> CH3COO- + H+ at 25°C
Then, [CH3COO-]=[H+]?
Is this valid at any temperature?

Thank you!
It is an approximation.

IF the only source of H+ ions is the dissociation of your weak acid, then it would be true.

BUT H+ can also come from the autodissociation of water.

i.e. at very low conc. of HA, the H+ from water becomes important and the approximation breaks down.

OR if Ka for your HA is very small, then the H+ from the HA is so small that the H+ from water again is important.
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Medikj
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(Original post by Pigster)
It is an approximation.

IF the only source of H+ ions is the dissociation of your weak acid, then it would be true.

BUT H+ can also come from the autodissociation of water.

i.e. at very low conc. of HA, the H+ from water becomes important and the approximation breaks down.

OR if Ka for your HA is very small, then the H+ from the HA is so small that the H+ from water again is important.
Ok, thank you!
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