STUDY OF MOLAR REFRACTION AND POLARIZABILITY CONSTANT OF AQUEOUS SOLUTIONS OF KNO3 AND KBrO3 AT DIFFERENT TEMPERATURES

ArunB. Nikumbh, MeenakshiV. Rathi
2017 International Journal of Advanced Research  
Densities and Refractive Indices of solutions of potassium bromate (KBrO 3 ) have been studied in water and 0.1%, 0.2%, 0.3%, 0.4% and 0.5% (w/v) aqueous solution of KNO 3 with temperature in the range T = 298.15˚K-313.15˚K. The data obtained is utilized to determine Specific Refraction (R D ) and Molar Refraction (R M ) of solutions. The values of Refractive indices, Molar Refraction (R M ) and Molar Polarizability (α) constant are found to be decreased with decreasing concentration of solute
more » ... n solvent and these results are also interpreted in terms of interaction in salt solution. It has been verified that Molar Refraction is additive and constitutive property. Copy Right, IJAR, 2017,. All rights reserved. ...................................................................................................................... Introduction:- The molar refractivity is a measure of the polarizability of the molecule [1]. The study of specific refractivity, molar refractivity and polarizability of salt solutions plays a vital role not only in chemical but also in engineering, medical and biotechnical field. The best part with measurement of refractive index is that it can be measured easily with a high degree of accuracy. Potassium bromate has been widely used in the oxidation of many organic compounds in acidic medium. Idris S.O. et al. [2] describe the kinetics of the oxidation of L-Methionine by potassium bromate in hydrochloric acid medium. The kinetics and mechanism of the oxidation of Tartaric acid by potassium bromate in perchloric acidic medium was also studied [3] . A combination of sulfuric acid and potassium bromate in the presence of SiO 2 were used as effective oxidizing agent for the oxidation of alcohol to its corresponding aldehyde and ketone derivatives in various organic solvents with good yield [4] .Potassium bromate as an oxidizing agent in a Titania-based Ru CMP slurry was studied by S. Noyel Victoria [5] . The toxic effect of KBrO 3 on vestibuloocular reflex system of human was studied [6] . Optical dispersion and Molar refractivities of Alkali Halide crystals and aqueous solutions were studied by A. Penzkofer, H. Glas[7] Measurement of refractive index is an essential and important work to study the thermodynamic and other physical properties such as specific refractivity, molar refractivity and polarizability of solutions which provide information about the molecular structure of the components used in the solutions. The molar refractivity reflects arrangements of the electron shells of ions in molecule and yields information about the electronic polarization of ions. Materials:- The chemicals (KNO 3 and KBrO 3 ) were of high purity (ACS reagent ≥ 99.0%) obtained from Sigma Aldrich, used directly without further purification. Potassium bromate and potassium nitrate are commercially available in the form of white crystals. Water used for solution preparation was triply distilled with specific conductance of < 10 -6 S .cm -1 . Aqueous solutions of KNO 3 of different percentage were prepared by dissolving an appropriate amount by weight of KCl in appropriate volume of water (w/v). The different concentrations of KBrO 3 in KNO 3 were prepared by diluting the stock solution. All weighing were done on electronic Contech balance having accuracy (0.0001g). Density measurements:-Density measurements were performed using bi-capillary pycnometer. The pycnometer was calibrated by measuring the densities of triple distilled water. The density was measured with an uncertainty of ± 1.48 × 10 -4 g.cm -3 . The temperatures were measured with an uncertainty of ± 0.01˚K. Refractive index measurements:- Refractive indices of different solutions were measured with the help of Abbe's refractometer. The refractive indices values are referred to a wavelength of 589.3 nm (Na, D-line). The temperature of prism box was maintained constant at required temperature by circulating water from thermostat. The refractometer was calibrated by glass test pieces of known refractive indices supplied with the instrument.
doi:10.21474/ijar01/3872 fatcat:ibopkgfzgjcb5iipe2akslj2rm