post lab 6
Jacob Hernandez
October 23, 2014
Hima Lahari Marneni
CHEM 1411. 114
Post Lab Report 6
Introduction
The purpose of this lab is to determine the concentration of HCl when titrated with a standardized NaOH solution, through means of the titration method. My hypothesis is When an unknown concentration of HCl is titrated with a known volume of standardized NaOH solution, one can gather enough data to determine the concentration of the unknown (HCl). My prediction is If an unknown concentration of HCl is titrated with a known volume of NaOH, then one can gather enough data to determine the concentration of the unknown which is HCl.
Procedure
Standardization of ~0.10M HCI
1- Weigh duplicate ~0.15 g samples of previously dried standard Na2CO3 Dissolve samples in ~100-ml distilled water; if it does not dissolve quickly, you may warm the solution.
2 - Cool the solution to room temperature and add ~ 0.5 to 1 ml of bromocresol green indicator,solution turns into blue. Titrate it with HCl until green color is reached. (DO NOT OVER TITRATE) 3 - Heat and boil out CO2gently. You should obtain a blue color again at the end of this step. Cool to room temperature, and continue titration until yellow color is reached. (DO NOT OVER TITRATE)
4 - Calculate the molarity of HCI, it should agree to about two parts per thousand. If they do not agree,repeat the procedure for the third time and take the avg. of the two closest results.
Standardization of ~0.10M NaOH
1- Weigh duplicate samples of 0.50-0.60 g of previously dried standard potassium hydrogen phthalate (KHP) into 250- ml flasks. Dissolve each sample in ~100- ml boiled distilled water.
2 - Cool to room temperature, add 2-4 drops of phenolphthalein indicator. Titrate it with NaOH until the first appearance of a permanent, pink color.
3 - Back titrate with your standard HCl if you miss the end point. Calculate the molarity of NaOH solution.
4 - If runs do not agree to about two parts per thousand, repeat for the third time
October 23, 2014
Hima Lahari Marneni
CHEM 1411. 114
Post Lab Report 6
Introduction
The purpose of this lab is to determine the concentration of HCl when titrated with a standardized NaOH solution, through means of the titration method. My hypothesis is When an unknown concentration of HCl is titrated with a known volume of standardized NaOH solution, one can gather enough data to determine the concentration of the unknown (HCl). My prediction is If an unknown concentration of HCl is titrated with a known volume of NaOH, then one can gather enough data to determine the concentration of the unknown which is HCl.
Procedure
Standardization of ~0.10M HCI
1- Weigh duplicate ~0.15 g samples of previously dried standard Na2CO3 Dissolve samples in ~100-ml distilled water; if it does not dissolve quickly, you may warm the solution.
2 - Cool the solution to room temperature and add ~ 0.5 to 1 ml of bromocresol green indicator,solution turns into blue. Titrate it with HCl until green color is reached. (DO NOT OVER TITRATE) 3 - Heat and boil out CO2gently. You should obtain a blue color again at the end of this step. Cool to room temperature, and continue titration until yellow color is reached. (DO NOT OVER TITRATE)
4 - Calculate the molarity of HCI, it should agree to about two parts per thousand. If they do not agree,repeat the procedure for the third time and take the avg. of the two closest results.
Standardization of ~0.10M NaOH
1- Weigh duplicate samples of 0.50-0.60 g of previously dried standard potassium hydrogen phthalate (KHP) into 250- ml flasks. Dissolve each sample in ~100- ml boiled distilled water.
2 - Cool to room temperature, add 2-4 drops of phenolphthalein indicator. Titrate it with NaOH until the first appearance of a permanent, pink color.
3 - Back titrate with your standard HCl if you miss the end point. Calculate the molarity of NaOH solution.
4 - If runs do not agree to about two parts per thousand, repeat for the third time