M. Meenachi and P. Krishnamurthi / Mechanica Confab ISSN: 2320-2491 Vol. 2, No. 2, February-March 2013 85 THEORETICAL PREDICTION OF REFRACTIVE INDEX OF PHENOL WITH HYDROCARBONS AT 303K M. Meenachi and P. Krishnamurthi Department of Physics, Jayam College of Engineering and Technology Dharmapuri- Tamilnadu, India-636813 Corresponding Email: drkrishnamurthi@gmail.com Abstract Refractive index of phenol with o-xylene, m-xylene, p-xylene have been measured at 303K over the whole mole fraction range were measured. The theoretical refractive index of binary mixtures was predicted using Arago-biot, Gladstone-Dale, Lorentz-Lorentz, Weiner, Heller, Newton and Eyring-John relations. The validity of these relations has been analyzed by comparing the experimental and theoretical refractive index. Comparison of various mixing rules has been expressed in terms of average percentage deviation. Keywords: Refractive Index, Density, Phenol, Xylene, Binary Mixtures, Hydrocarbon, Mixing Rules 1. Introduction This work is continue of our research on thermodynamic properties of system with phenol and xylenes and it presents the experimental data containing density and refractive indices of binary mixtures at 303K and excess parameters have been computed [1]. Many researchers have been studied the theoretical refractive index measurements by the refractive index mixing rules [2-5]. The generally used theoretical rules are Arago-biot, Gladstone- Dale, Lorentz-Lorentz, Weiner, Heller, Newton and Eyring-John. The validity of the mixing rules has been tested by several researchers pointed out the important of mixing rules [6-10]. In the present study, we report the experimental and theoretical refractive index of binary mixtures, from these the validity of the mixing rules have been analyzed. 2. Experimental The samples of phenol, o-xylene, p-xylene, and m-xylene were used in the present work. Chemicals are further purified according to the methods described by Riddick et al [11]. The refractive indices of liquid mixtures were measured using Abbe’s refractometer by using sodium D-Line at 303K. The temperature in the refractometer was regulated by using a circulation of pump connected with a constant temperature water bath a 0.01 o C stability. 3. Theory Theoretical refractive index of binary mixtures of phenol with hydrocarbon like o- xylene, p-xylene and m-xylene has been predicted by using the various theoretical relations.