Chemical Forums

Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Terrpatchio on March 01, 2007, 11:05:50 AM

Title: Volhard's Method
Post by: Terrpatchio on March 01, 2007, 11:05:50 AM
I was just wondering why in the Volhard method it doesnt make use of a blank titration, when it is usually customary to perform a blank titration for other titrations.
Title: Re: Volhard's Method
Post by: AhmedEzatAlzawalaty on March 07, 2007, 03:31:21 PM
the Volhard method is for direct determination of silver when the ep is detected by formation of soluble coloured comolex.and indirect determination of halides and u know how.so why the need to blank?
Title: Re: Volhard's Method
Post by: Borek on March 07, 2007, 05:12:58 PM
Quote from: ahmedezat on March 07, 2007, 03:31:21 PM
so why the need to blank?

Do you know - in general - why do we do blank?
Title: Re: Volhard's Method
Post by: AhmedEzatAlzawalaty on March 20, 2007, 03:49:52 PM
tell me You Mr why we do it.
Title: Re: Volhard's Method
Post by: ARGOS++ on March 20, 2007, 05:58:09 PM
Dear Terrpatchio,  Dear ahmedezat,
What you believe, that FDA, USP, EP, GLP, ISO 900x, and other such
regulatory’s will tell you, if you have forgotten, - or so -, to do a blank,
even if in history it was different?
Answer: “You are allowed to sell your product anywhere, but
never in US, or GB, or Germany, or … !"

Nice view, isn’t it?
Good Luck!
                    ARGOS++


Title: Re: Volhard's Method
Post by: AhmedEzatAlzawalaty on March 21, 2007, 08:31:21 AM
so why we do blank?
Title: Re: Volhard's Method
Post by: ARGOS++ on March 22, 2007, 06:36:45 AM
Dear ahmedezat,

(First:  Thank you for your Mail, - It makes me proud!)

I just realised, from both your questions, that you need a more
general answer to this/Your problem, and that means a more
philosophic one,  — “A Picture”:

 A.)  ALL POSSIBLE experiments/measurements are Questions to
       Mother Nature !!!
 B.)  Mother Nature holds the only contract, that HER answer is
       ALL THE TIME, as COMPLETE as POSSIBLE for
       the selected/designed (YOUR settings/design !!) of the
       experimental environment !!
 C.)  That means nothing else, as that you have ALL the TIME to
       use the following formula for your experiments/measurements (E/M)
       and your got Signal (S):
                        ?
       S(E/M)   =   ? Sj   =  S1 + S2 + Si + S4 + S5 + ……..          (Eq. 1)
                        j
       (Have You seen:     Si = Signal of interest !!!)
 D.)  Quintessence:  You HAVE TO EXTRACT your Si,  ? of course, only
       if you prefer to be reliable:
       Si   =   S(E/M) ?  (S1 + S2 +  0.0000  + S4 + S5 + ……..)    (Eq. 2)
 E.)  Now you may realise, that the (Residual-)Term in Eqiation 2, after
       the Minus-Sign, is nothing else, as the Signal of your selected/designed
       Environment, called:
          The Blank   OR   Reference(in spectroscopy)  OR   ……   =  Senv.

       So the (Residual-)Term is also the Recipe, “How to do it”,  — 
       Make the identical experiment “with the Concentration”:   
                     Conci = 0.0000 !!!
 
Have You realized, to make “A Picture” of  “Everything plus one”, if possible THE correct, is ALL TIMES the most important to do,  —
But especially for to have success!!

Sorry, if it finally empowered a little too moralistic for You, But specially for the Others.

Good Luck!
                    ARGOS++