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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: becchino on December 20, 2018, 03:26:05 AM

Title: Assay Formula
Post by: becchino on December 20, 2018, 03:26:05 AM
Hi, i have a question.

Can you help me find correct formula to calculate Assay?
The product is dibasic.
Thank you

SODIUM CITRATE
Natrii citras
C6H5Na3O7,2H2O



ASSAY
Dissolve 0.150 g in 20 mL of anhydrous acetic acid R, heating to about 50 °C. Allow to cool. Titrate with 0.1 M perchloric acid, using 0.25 mL of naphtholbenzein solution R as indicator until a green colour is obtained.
1 mL of 0.1 M perchloric acid is equivalent to 8.602 mg of C6H5Na3O7

Title: Re: Assay Formula
Post by: sjb on December 20, 2018, 04:35:20 AM
Not quite sure what you mean by "correct formula to calculate Assay" - do you mean a balanced equation or something?

The maths has already been done for you in the last sentence.
Title: Re: Assay Formula
Post by: becchino on December 20, 2018, 04:59:30 AM

I mean the complete formula for calculating Assay.

For example


ml sample * 8.602 * 100 * 100
___________________________
Sample Weight * (100 - Waters%)



But this formula I think is incorrect