I had a question on neutralizing a strong acid with a weak base. I'm not much for chemistry and I've always hated it more or less due to the tedious mathematical aspects and rules. As I understand it, generally a lower pH means a strong acid, and a higher pH means a strong base, but this only talks about the molar concentration in a logarithmic scale. From this information alone, I can't extrapolate a good sense of the actual ability of an acid and base to combine and neutralize each other or the rate at which they donate their respective ions. If I have pure baking soda and it donates an OH- ion, why exactly would that not be enough to neutralize the same amount of moles of something a like pure hydrofluoric acid ion (HF+) if HF only donates a single H+ ion? You got one OH- ion and one H+ ion when they interact with each other, why isn't the same amount of molecules of both hydrofluoric acid and baking soda enough to completely neutralize each other?

Just ignore any other properties of baking soda that might make this scenario not work, just assume chemical x has a pH of 7.1 and donates a single H+ ion per interaction, and chemical y has a pH of 2 and donates a single H+ on.

Edited December 26, 201312 yr by Colic

Firstly, baking soda is a bit more complicated than that and you appear to be using a very restrictive definition of acids and bases; I would advise you to perhaps look up Bronsted-Lowry and Lewis definitions. Baking soda, NaHCO3, typically reacts with acids to form CO2, H2O and a sodium salt. HF is monoprotic and highly corrosive, but it is not a strong acid just as sodium bicarbonate is not a strong base (meaning they do not fully dissociate in water) and you would likely need more than a 1:1 ratio to get to the equivalence point (though your pH still may not be 7). You may want to read this: http://chemwiki.ucdavis.edu/?title=Physical_Chemistry/Acids_and_Bases/Ionization_Constants/Acid_and_Base_Strength/Weak_Acids_%26_Bases

 

Secondly, you can get an idea of acid strength by looking at pKa's or base strength by looking at pKb's. These are the logs of the acid / base dissociation constants and may be determined experimentally, or simply by looking them up.

 

Your second paragraph makes no sense and I am not sure what you're asking. What is all of this for?