Introducing of Thermodynamic Van’t Hoff Equation in Process of Dissociation of Benzoic Acid at Ordinary Temperature Range

Abstract

In article, we have reported the thermodynamic Van’t Hoff equation in study of dissociation process of solute benzoic acid into water solvent at ordinary temperature in between of 288 K to 318 K. At this temperature range, the value of dissociation constant (Kc) of that acid is being to found as -4.169, -4.045, -3.993, -3.885, -3.848 and -3.788, for given concentrations of NaCl (sodium chloride) volume as its six ionic strength of 0.00, 0.05, 0.10, 0.30, 0.40 and 0.50 M, respectively, which are titrimetrically analyzed with 0.05 M basic NaOH (sodium hydroxide) solution. The pH value of each solution is measured by using of digital pH-meter as well. Here, observation reported that the pH value of benzoic acid into water at that range of temperature is being inversely related to concentrations of NaCl. In graph, a value of benzoic acid with there ionic strength (I) is plotted versus equilibrium dissociation constant (Kc) at specific 298 K, have shown the dissociation of acid into water is increases as increase the ionic strength. But, comparatively, the graph for increasing temperature range to thermodynamic dissociation constant (Ka) have shown that the dissociation is not always increases as if increases temperature.

Thermodynamic Based Aqueous Solvation and Dissociation of Benzoic Acid

“…The value of ∆G is depends almost entirely on the entropy change (∆S) associated with the enthalpy (∆H) of process at condition of temperature and pressure. In finding of precious results for benzoic acid salvation into aqueous we are applying Gibbs thermodynamic relation (7) at constant condition where its parameters value are being as ∆G = 12.507 kJ.mol -1 , ∆H = 3.823 kJ.mol -1 and ∆S = -29.14 kJ.mol -1 . From using of equation 9 we can calculated the salvation free energy change of benzoic acid.…”

“…Notably, the each solute substances having a specific solvation and dissociation properties into a given solvent, which is depends on various factors such as pressure, temperature, intermolecular forces, bonding and polarity of substances etc [1][2][3]. A slightly changing is appears due to solute-solvent interactions when by addition of small amount of solute into water like solvent, then it trying to dissolve in it and get ionizes with their ionic strength in respect of temperature [4][5][6][7]. Although, the distribution of solute into solvent have well reported by W. Nernst (1891) with given a partition law, K = C A /C B [8].…”

Phenolphthalein Indicator in Titrimetric Estimation of Benzoic Acid Solubility and Distribution in Water and Benzene-Buffer Solutions

“…The observation of graph indicates that, the partitioning of benzoic acid in acidic pH medium is higher in comparison of neutral or in basic medium [23]. Although, the solubility of benzoic acid is thermodynamically dependent [24,25], and follow to Van't Hoff equation [26].…”

Gibbs Free Energy Change (∆G) in Aqueous Dissociation of Benzoic Acid at Temperature ‘K’: A Thermodynamic Study

“…Indeed, the each solute substances having a specific solubility or dissociation into a given solvent, which is depends on various factors such as pressure, temperature, intermolecular forces, bonding and polarity of substances etc [1][2][3]. A slightly changing is appears due to solutesolvent interactions when by addition of small amount of solute into water like solvent, then it trying to dissolve in it and get ionizes with their ionic strength in respect of temperature [4][5][6][7][8]. Although, the dissociation of solute into solvent have earlier reported [9], but, it proved well by Nernst in 1891 with given partition law, K = C A /C B [10].…”