Molecular formula: C7H5NaO2
Molecular Weight: 144.11
Assay: Weigh accurately about 1.5 g of sodium benzoate, previously dried at 110°C and dissolved in 25 mL of water, add 75 mL of ether, and titrate with 0.5 M hydrochloric acid using bromophenol blue as an indicator. Perform the titration dropwise by shaking the aqueous and ethereal layers until a light green color persists in the aqueous layer.
Reaction:
Factor Calculation:
1 Mole of HCl ≅ 1 Mole of Sodium Benzoate
1000 mL of 1M HCl ≅ 144.11 g of C7H5NaO2
1 mL of 0.5M HCl ≅ 0.07205 g of C7H5NaO2
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