standardization
Standardization of a NaOH Solution with Potassium Hydrogen Phthlate (KHP)
Name:________________________________________________________________ Period:_____
Prelab
1. A 0.8234-g sample of "KHP" required 38.76 mL of NaOH for titration to the phenolphthalein endpoint. What is the exact molarity of the NaOH solution?
2. A 25.00-mL aliquot of an unstandardized HCl solution is titrated with the previously standardized NaOH solution from #1 above. If 32.55 mL of NaOH titrant is required to reach the endpoint, what is the exact molarity of the HCl solution?
3. How accurately can you estimate the buret reading on a 50-mL buret that has calibration markings every 0.1mL? (Circle the correct answer)
a) 1 mL b) 0.1 mL c) 0.01 mL d) 0.001 mL
4. Why should the sample size be such that not more than 50 mL of titrant is required to reach the endpoint?
5. What mass (in grams) of "KHP" should be used for the standardization of a NaOH solution that is approximately 0.14 M NaOH if the volume of NaOH titrant used is to be about 45 mL? (Approximate calculation - 2 sig. figs is adequate)
Standardization of a NaOH Solution with Potassium Hydrogen Phthalate (KHP)
Objective You will determine the concentration (standardize) of an unknown solution of NaOH using the primary standard, potassium hydrogen phthalate.
Introduction
Sodium hydroxide is hygroscopic and absorbs water from the air when you place it on the balance for massing. This water will prevent you from being able to find the exact mass of sodium hydroxide. In order to determine the exact concentration of a sodium hydroxide solution you must standardize it by titrating with a solid acid that is not hygroscopic. Potassium hydrogen phthalate, KHC8H4O4 (abbreviated KHP), is a non-hygroscopic, crystalline, solid that behaves as a monoprotic acid. It is water soluble and available in high purity. Because of its high purity, you can determine the number
Name:________________________________________________________________ Period:_____
Prelab
1. A 0.8234-g sample of "KHP" required 38.76 mL of NaOH for titration to the phenolphthalein endpoint. What is the exact molarity of the NaOH solution?
2. A 25.00-mL aliquot of an unstandardized HCl solution is titrated with the previously standardized NaOH solution from #1 above. If 32.55 mL of NaOH titrant is required to reach the endpoint, what is the exact molarity of the HCl solution?
3. How accurately can you estimate the buret reading on a 50-mL buret that has calibration markings every 0.1mL? (Circle the correct answer)
a) 1 mL b) 0.1 mL c) 0.01 mL d) 0.001 mL
4. Why should the sample size be such that not more than 50 mL of titrant is required to reach the endpoint?
5. What mass (in grams) of "KHP" should be used for the standardization of a NaOH solution that is approximately 0.14 M NaOH if the volume of NaOH titrant used is to be about 45 mL? (Approximate calculation - 2 sig. figs is adequate)
Standardization of a NaOH Solution with Potassium Hydrogen Phthalate (KHP)
Objective You will determine the concentration (standardize) of an unknown solution of NaOH using the primary standard, potassium hydrogen phthalate.
Introduction
Sodium hydroxide is hygroscopic and absorbs water from the air when you place it on the balance for massing. This water will prevent you from being able to find the exact mass of sodium hydroxide. In order to determine the exact concentration of a sodium hydroxide solution you must standardize it by titrating with a solid acid that is not hygroscopic. Potassium hydrogen phthalate, KHC8H4O4 (abbreviated KHP), is a non-hygroscopic, crystalline, solid that behaves as a monoprotic acid. It is water soluble and available in high purity. Because of its high purity, you can determine the number