Benzoic Acid And O-Toluic Acid Lab Report

The specific purpose of this experiment is to determine the composition of vapor and liquid phases for different mixtures of a pair of volatile liquids using refractive values and distillation techniques involving the construction of two different types of phase diagrams. Moreover, these different phase diagram might be analyzed and compared individually in order to have a better understanding about the multiple types of phase equilibrium and phase change that occurs. For the procedure, the two components are benzoic acid and o-toluic acid. The first step of this experiment is to accomplish the part A: run samples A1 to A5 and B1 to B5. For this step, place a beaker of silicon oil on top of a hot plate until the temperature reaches 135 +/-

Firstly, measure the refractive index of water five times and then measure for each of the pure liquids (toluene and cyclohexane). After that prepare 9 mixtures of toluene and cyclohexane carrying their volume fractions from 10 to 90 percent in increments of 10 percent using 10.0 mL volumetric flasks. The last step is to read the temperature in the thermometer. Then, determine the the boiling point for toluene and for cyclohexane. Finally, complete the part C: for this part, the composition of vapor and liquid phases of toluene-cyclohexane mixtures. From the done experiment result were successfully obtained regardless some errors. The resulting liquid-vapor phase diagram for toluene and cyclohexane vs. temperature demonstrates that as the temperature increases, the components leave the liquid phase reaching the vapor phase. For this plot, the equilibrium region is the the region enclosed by the two curves (liquid and vapor). The 40% o-toluic acid phase diagram has an equation with negative slope indicating that all the components are in solid phase: y = -0.1236x +

To take the refractive index, ten different mixtures were prepared in which each of them contains different cyclohexane and toluene concentration in increments (total volume of mixture 10 mL). After that, the corrected refractive index in found in order to plot the refractive index vs. mole fraction of toluene; the equation from this plot will allow the calculation of toluene’s molar fraction in the distilled mixture. After this calculation, the remaining molar fraction of toluene (gas phase) is used to plot Liquid - vapor phase diagram for toluene and cyclohexane vs. temperature (fig.1). This plot contains two curves representing two phases – vapor and liquid; the region between liquid and vapor curve is the equilibrium region (liquid and vapor). From the vapor phase diagram for toluene and cyclohexane vs. temperature, it might be concluded that as the temperature increases, the components change their phase from liquid to vapor phase (Fig. 1). The refractive indices values obtained for toluene and for cyclohexane are accurate since their values is closed to the known value and the percent of error is very small. The values for the temperature boiling point are precise. Factor such as the not correct reading of the temperature might be one of the reason for the fond error. In this case, the lever