Formation Of P-Toluenesulphonic Acid Lab Report

Experimental set-up

Observations

Figure 1 Figure 2 Figure 3

Figure 1 show the crystallisation reaction when the saturated sodium chloride solution was added to the cool reaction mixture. The salt of p-Toluenesulphonic acid started forming.

Figure 2 show the wet crystal after the precipitated salt was being filtered by suction. The wet crystal was light purple in colour.

Figure 3 show the end product after drying the wet crystal at 105°C in the drying cabinet (oven). The end product that we got is a black liquid instead of the expected white crystal.

Analysis and Conclusion of Observations

We did not manage to get the dry crystal as our end product. Instead we got a black liquid as our end product. This could be because the temperature of 105°C was too high for drying the crystals. The crystals should be dry at a lower temperature.

Questions
of moles of toluene = Mass/Mr = 43.35g/(92.15g/mol) = 0.470428648 moles ≈ 0.470 moles

Volume of Sulphuric acid = 10mL (10cm3)
Density of Sulphuric acid = 1.84g/cm3
Mass of Sulphuric acid = Density x Volume = 1.84g/cm3 x 10cm3 = 18.4g
Mr of Sulphuric acid = 98.09g/mol
No. of moles of Sulphuric acid = Mass/Mr = 18.4g/(98.09g/mol) = 0.187582832 moles ≈ 0.188 moles

Limiting reagent: Sulphuric acid

No. of moles of p-Toluenesulphonic acid = 0.188 moles
Mr of p-Toluenesulphonic acid = 172.22g/mol
Mass of p-Toluenesulphonic acid = Moles x Mr = 0.188 moles x 172.22g/mol = 32.37736g ≈ 32.4g

Volume of NaCl solution = 100mL (100cm3)
Density of NaCl solution = 2.16g/cm3
Mass of NaCl solution = Density x Volume = 2.16g/cm3 x 100cm3 = 216g
Mr of NaCl solution =