So I'm titrating salicylic acid with NaOH solution... is the ratio 1:1 or 1:2? This is a simple question but I'm having the damndest time finding it out. All I can get on the google machine is acetylsalicylic acid which is not what I need. I appreciate the help. Also, please site sources otherwise I won't believe you :)

its 1:1. it has one acidic proton, as is obvious from the structure.

I think RAOVQ is right, but I appreciate your confusion.

In phenol, the hydroxyl proton is relatively acidic [pKa~10 (water)], and can be fully deprotonated by a solution of NaOH (say 1M).

The CRC handbook gives a value for the 2nd pKa of salicylic acid as 13.6, so this could also theoretically be deprotonated by NaOH. Interestingly, the pKa here is much higher than that analagous 3- and 4-hydroxy benzoic acids - this is likely to be a result of intramolecular hydrogen bonding between the carboxylate oxygen and the phenolic hydrogen. This arrangement could lead to the formation of a 6-membered ring and provide a degree of resistance to further deprotonation.

However, for your purposes I think it's safe to say that the end point of the titration would be reached after full deprotonation of the acid function, thus giving a ratio of 1:1

to be honest, the whole idea of titrating a molecule in water with a phenol is just stupid. the end point is going to be so weak that you may as well just guess what the conc is and save some time.

the difference in pkas should be big enough to only pretend that one proton is removed, unless you used an indicator that changes at like pH12 or something.

anything with a pka > 7 cannot be titrated accurately in water. if a titration is required, then a basic solvent like en should be used instead of water.

Well, yes - I think the difficulties in acid/base titration of phenol and the like are well known, I was merely highlighting a point of interest...

its 1:1. it has one acidic proton, as is obvious from the structure.

As is obvious... haha. It has two protons dumb shit. I didn't know pKa2 for it and couldn't find that crap. Maybe my google skills need work. You arrogant, ignorant cunt. Of course it's not going to be the most accurate thing. School labs need to worry about cost. Even my quantitative analysis lab used 50 mL burettes accurate only to .1 mL; we were still expected to be accurate to 3% of the true value. Thanks for your worthless, unasked for opinion though.

Thanks for the help from others.

As is obvious... haha. It has two protons dumb shit. I didn't know pKa2 for it and couldn't find that crap. Maybe my google skills need work. You arrogant, ignorant cunt. Of course it's not going to be the most accurate thing. School labs need to worry about cost. Even my quantitative analysis lab used 50 mL burettes accurate only to .1 mL; we were still expected to be accurate to 3% of the true value. Thanks for your worthless, unasked for opinion though.

Thanks for the help from others.

Hey fuck face, wrong or not, he still tried to help your worthless ignorant ass. So go get bent and die in a fire :mad::cool:

As is obvious... haha. It has two protons dumb shit.

Christ!

Calm down!

It actually has 6 protons, two of which may be considered acidic


I didn't know pKa2 for it and couldn't find that crap.

It's 13.6 - it's in the CRC handbook. It's also in my reply.


Thanks for your worthless, unasked for opinion though.

You did ask, and he actually gave you the correct answer - or at least a close enough approximation for your purposes...


Thanks for the help from others.

Anytime ;)