determination of carbonic acid
Procedure:
Melting point of RCO2H
Before observing the melting point of the unknown sample, the melting apparatus had to be standardized with a standard substance having the melting point of 151°C-153°C. After placing a small sample of the standard in a capillary tube and inserting the tube into the sample tube holder, the plateau on the device was set to 15°C below the expected melting point. After its temperature reached the plateau, the temperature increment was set at 1°C per minute, and the melting point range of 152°C-154°C was recorded. After standardizing the melting device, a small sample of unknown carboxylic acid was placed in a capillary tube, and an arbitrary plateau of 200°C was set. When the sample started to melt at 150°C, another capillary tube containing a small amount of unknown sample was placed in the melting device, and the plateau was set to 135°C, 15°C below the expected melting point. After its temperature reached the plateau, the temperature increment was set at 1°C per minute, and the melting point range of 147°C -149°C was recorded for the unknown sample.
Titration of KHP with NaOH
In this part the molarity of diluted NaOH was determined. After mixing 800 mL of water with 4.2 mL of 19.1 M NaOH, the diluted solution of NaOH was poured in a buret until the initial volume on the buret was 30.00 mL. 0.3005g of KHP was dissolved in 40.0 mL of 50% ethanol, and a drop of indicator was added to the Erlenmeyer flask containing the KHP solution. When the titration of KHP solution with NaOH reached its endpoint, pale pink color was observed, the final volume of NaOH in the buret, 45.00 mL, was recorded. Based on the data obtained and the equivalent weight of KHP, 204.24g/eq, the molarity of the NaOH was calculated.
Molarity of NaOH=(Weight of KHP Sample(g))/(Eq.Wt.of KHP * Volume of NaOH(L))=□(0.3005g/(204.24 g/eq*0.015L))=0.09809
Two more trials were performed, and the related data are tabulated in Table 1.
Titration of HCl with NaOH
To be
Melting point of RCO2H
Before observing the melting point of the unknown sample, the melting apparatus had to be standardized with a standard substance having the melting point of 151°C-153°C. After placing a small sample of the standard in a capillary tube and inserting the tube into the sample tube holder, the plateau on the device was set to 15°C below the expected melting point. After its temperature reached the plateau, the temperature increment was set at 1°C per minute, and the melting point range of 152°C-154°C was recorded. After standardizing the melting device, a small sample of unknown carboxylic acid was placed in a capillary tube, and an arbitrary plateau of 200°C was set. When the sample started to melt at 150°C, another capillary tube containing a small amount of unknown sample was placed in the melting device, and the plateau was set to 135°C, 15°C below the expected melting point. After its temperature reached the plateau, the temperature increment was set at 1°C per minute, and the melting point range of 147°C -149°C was recorded for the unknown sample.
Titration of KHP with NaOH
In this part the molarity of diluted NaOH was determined. After mixing 800 mL of water with 4.2 mL of 19.1 M NaOH, the diluted solution of NaOH was poured in a buret until the initial volume on the buret was 30.00 mL. 0.3005g of KHP was dissolved in 40.0 mL of 50% ethanol, and a drop of indicator was added to the Erlenmeyer flask containing the KHP solution. When the titration of KHP solution with NaOH reached its endpoint, pale pink color was observed, the final volume of NaOH in the buret, 45.00 mL, was recorded. Based on the data obtained and the equivalent weight of KHP, 204.24g/eq, the molarity of the NaOH was calculated.
Molarity of NaOH=(Weight of KHP Sample(g))/(Eq.Wt.of KHP * Volume of NaOH(L))=□(0.3005g/(204.24 g/eq*0.015L))=0.09809
Two more trials were performed, and the related data are tabulated in Table 1.
Titration of HCl with NaOH
To be