• British Pharmacopoeia Volume IV
  • Appendices
  • Appendix I A. General Reagents

Sodium Hydroxide
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Sodium Hydroxide NaOH  =  40.00 (1310-73-2)

Analytical reagent grade of commerce containing not less than 97% of total alkali calculated as NaOH and not more than 2.0% of Na2CO3.

White, deliquescent pellets, sticks or slabs.

Assay Dissolve 2  g in 25  ml of water and add 25  ml of barium chloride solution R1 and 0.3  ml of phenolphthalein solution . Titrate with 1m hydrochloric acid VS , add 0.3  ml of bromophenol blue solution and continue the titration with 1m hydrochloric acid VS . Each  ml of 1m hydrochloric acid used in the second part of the titration is equivalent to 52.99  mg of Na2CO3. Each ml of 1m hydrochloric acid VS used in the combined titrations is equivalent to 40.00  mg of total alkali, calculated as NaOH.

Store in an airtight container.