Review of effect of temperature and thermodynamic quantities upon acidic dissociation of Glycine in 10, 20 and 30% dioxane (m/m) in dioxane-water system at 288.15K, 298.15K, 308.15K and 318.15K by e.m.f. measurement

Abstract

<p>For study of effect of temperature and thermodynamic quantities upon acidic dissociation of Glycine in 10, 20, and 30% dioxane(m/m) content in dioxane-water system at 288.15K, 298.15K, 308.15K, and 318.15K, the following types of cell has been set up:</p> <p>H₂(Pt) | Glycine, HCl, X% Dioxane, Hg₂Cl₂| Hg</p> <p>m₁ m₂ (C-1)</p> <p>in 10, 20, and 30% dioxane in dioxane-water system at 288.15K to 318.15K at an interval of 10K, and e.m.f. of the cell was given by:</p> <p>E = E⁰ - (2.303RT/F) (log m_H⁺ m_Cl^_ + log Ɣ_H⁺ Ɣ_Cl^_) (1)</p> <p>where,</p> <p>log Ɣ_H⁺ Ɣ_Cl^_ = - (2A`√μ/(1+√μ) ) + b<sub>1</sub>μ (2) </p> <p>log K<sub>1</sub> - b<sub>1</sub>μ = log K<sub>1</sub>(A) – (2A`√μ/(1+√μ)) (3)</p> <p>The equation (2) is called Modified Davies equation given by B. Prasad¹ for calculating activity coefficient in the system.</p> <p>From equation (3), acidic dissociation constant of glycine was calculated^2-5 by extrapolating the graph at μ=0 in 10, 20, and 30% dioxane (m/m) in dioxane-water system from 288.15K to 318.5K at an interval of 10K, and then standard free energy change, standard enthalpy change, and standard entropy change were calculated by thermodynamic relations:</p> <p> ΔG⁰ = -RTlnK₁ (4)</p> <p>and ΔG⁰ = ΔH⁰- TΔS⁰ (5)</p> <p>and by least square method⁶.</p>