Sodium Hydroxide VS

NaOH = 40.00

For a 0.1m solution Dilute 100.0 mL of 1 M sodium hydroxide to 1000.0 mL with carbon dioxide-free water.

Standardisation Carry out the titration described for 1 M sodium hydroxide using 0.150 g of potassium hydrogen phthalate in 50 mL of water.

1 mL of 0.1 M sodium hydroxide is equivalent to 20.42 mg of C₈H₅KO₄.

Standardisation (for use in the assay of halide salts of organic bases). Dissolve 0.100 g of benzoic acid in a mixture of 5 mL of 0.01 M hydrochloric acid and 50 mL of ethanol (96 per cent). Carry out the titration (2.2.20), using the sodium hydroxide solution. Note the volume added between the 2 points of inflexion.

1 mL of 0.1 M sodium hydroxide is equivalent to 12.21 mg of C₇H₆O₂.

For a 1m solution Dissolve 42 g of sodium hydroxide in carbon dioxide-free water and dilute to 1000.0 mL with the same solvent.

Standardisation. Dissolve 1.50 g of potassium hydrogen phthalate in 50 mL of water. Titrate with the sodium hydroxide solution, determining the end-point potentiometrically (2.2.20) or using 0.1 mL of phenolphthalein solution as indicator.

1 mL of 1 M sodium hydroxide is equivalent to 204.2 mg of C₈H₅KO₄.

If sodium hydroxide free from carbonate is prescribed, prepare it as follows. Dissolve sodium hydroxide in water to give a concentration of 400-600 g/L and allow to stand. Decant the clear supernatant, taking precautions to avoid the introduction of carbon dioxide, and dilute with carbon dioxide-free water to the required molarity. The solution complies with the following test. Titrate 20.0 mL of hydrochloric acid of the same molarity with the solution of sodium hydroxide, using 0.1 mL of phenolphthalein solution as indicator. At the end-point add just sufficient of the acid to discharge the pink colour and concentrate the solution to 20 mL by boiling. During boiling add just sufficient acid to discharge the pink colour, which should not reappear after prolonged boiling. The volume of acid used does not exceed 0.1 mL.