| 1 M Sodium Hydroxide |
| 1.0 Scope: This procedure is applicable for preparation and standardization of 1M sodium hydroxide solution. 2.0 Apparatus: 2.1 1000 ml volumetric flask 2.2 250 ml glass-stoppered, conical flask 2.3 100 ml graduated pipette 2.4 100 ml volumetric flask 3.0 Reagents: 3.1 NaOH AR grade 3.2 Potassium hydrogen phthalate AR grade 3.3 Phenolphthalein solution 3.4 Ethanol (95%v/v) To read this SOP click here Preparation of 1 M Sulphuric acid. 4.0 Preparation of reagent: Phenolphthalein solution: Dissolve about 1g of phenolphthalein in ethanol (95%v/v) and dilute 100 ml. Store in a well fitted transparent glass bottle. 5.0 Preparation: Dissolve about 42 g of sodium hydroxide(NaOH) in sufficient purified/milli-Q water to produce 1000 ml. Transfer the solution in a cleaned, dried and well stoppered plastic bottle. Keep the solution at least for an hour. 6.0 Standardization: Weigh accurately and transfer about 5.0 g of potassium hydrogen phthalate(PHP), previously powdered and dried about 120 degree Celsius for 2 hours to a 250 ml glass stoppered conical flask. and dissolve in 75 ml of purified/milli-Q water. Add 0.1 ml of phenolphthalein solution and titrate with the sodium hydroxide solution until a end point permanent pink colour is produced. Each ml of 1M sodium hydroxide is equivalent to 0.2042 g of C8H5KO4. 7.0 Calculation: Weight of PHP X 1N= ————————– V X 1 Where: N = Molarity of 1M NaOH solution Weight of PHP = weight of potassium hydrogen phthalate in gm. V = volume of 1M sodium hydroxide solution in ml 8.0 Storage: Store in a well fitted transparent glass bottle. |