[becchino]

What's the mean of this?

0.1 M Sodium hydroxide. 3006600.
Dilute 100.0 ml of 1 M sodium hydroxide to 1000.0 ml with
carbon dioxide-free water R.
Standardisation. Titrate 20.0 ml of the sodium hydroxide
solution with 0.1 M hydrochloric acid, using the end-point
detection prescribed for the assay in which the 0.1 M sodium
hydroxide is used.
Standardisation (for use in the assay of halide salts of
organic bases). Dissolve 0.100 g of benzoic acid RV in a
mixture of 5 ml of 0.01 M hydrochloric acid and 50 ml of
alcohol R. Carry out the titration (2.2.20), using the sodium
hydroxide solution. Note the volume added between the 2
points of inflexion.


ssay of halide salts of organic bases? For example???

Thanks

[Arkcon]

It means you've copied out a section of a pharmacopia.  I often just reference a page of the pharmacopeia on this forum, as a starting point to help someone.  Do you have specific question in mind?  With a few questions of yours posted on this forum, , you should be aware of the Forum Rules{click}, we want to see your attempt. Just asking, "explain everything" isn't a useful question.  What is the analyte in question?  We might be able to understand this procedure with that context.

[becchino]

Sorry, I misspoke the question. This is the standardization of NaOH pharmacpoea.
But what does the phrase " Standardisation (for use in the assay of halide salts of organic bases)"
What is "halide salts of organic bases"?
Thanks

[Arkcon]

What is an organic base? http://en.wikipedia.org/wiki/Organic_base
What is a halide? http://en.wikipedia.org/wiki/Halide
What is a salt? http://en.wikipedia.org/wiki/Salt_%28chemistry%29

So what is a halide salt of an organic base?

I'm sorry to answer questions with questions, but that's how we do things here, we want to help you learn to help yourself.

I'm sorry to send you straight to Wikipedia, but we like people who post here to know, its a good resource for beginner questions.

If you don't know what an organic salt of a halide is, that's not a catastrophe, but why are you asking, if you have no idea?  I mean to say, why are you trying to perform these sorts of analysis, without the fundamentals? 

Anecdotally, organic base groups are common in medicines, because they interact reversibly with molecules already within us.  Unfortunately, they don't dissolve well in water.  But, organic bases, neutralized with acids, into the slat of the base, do dissolve well in water.  Is that what you wanted to know?  Because you are working off of a pharmacopeia, after all.  This topic should be on your mind.

Are you wondering why the procedure is different?  I don't really know, the phamacopias aren't really big on explaining or referencing their procedures.  I can guess you might get a different sort of response from the titration against a weak organic acid (that's what you'll get when you neutralize a weak base, the organic with a strong acid, the HCl, HF, HBr, or HI) so they want the titer to reflect that response. 

[becchino]

hello.
I have to translate the pharmacopoeia in Italian for my lab.
The problem is that I can not translate this:
when I have to use standardization NaOH with HCl and when with Benzoic Acid?
Whenever the operator must analyze the molecule to know what method to use?
Thank You

[Arkcon]

hello.
I have to translate the pharmacopoeia in Italian for my lab.

You should probably just buy the EU pharmacopiea in Italian.  Government auditors may take a dim view of you working off a document in a language you're not fluent in.

The problem is that I can not translate this:
when I have to use standardization NaOH with HCl and when with Benzoic Acid?

Well, the English translation you gave us is clear enough to me.  You determine the titer of the NaOH by the second method when you need that NaOH solution to titrate  (... in the assay of halide salts of organic bases)  Like I told you, this describes many medicines.  As an example, oxycodone is a large molecule that contains an organic base group, it is used as a medicine in a number of salt forms, one of them, the hydrochloride:  http://en.wikipedia.org/wiki/Oxycodone#United_States_2

Whenever the operator must analyze the molecule to know what method to use?

Depending on the molecule.  I can only guess what the problem is, if you have to assay citric acid, for say a foodstuff or a vitamin mixture, you use NaOH standardized by method one, if you're analyzing oxycodone hydrochloride, you use NaOH standardized by the second method.

If you don't know what you have, then you do nothing, until you do know what you have.  If you're working off of a pharmacopeia, then you're likely in a regulated environment, making mistakes here can have serious ripercussioni.