INVESTIGATION OF ACOUSTICAL PARAMETERS OF N-(2'-HYDROXY-3'-NITROBENZYLIDENE) -3-SUBSTITUTED PYRIDINE-2-AMINE SCHIFF BASE DERIVATIVES IN DIOXANE-WATER MIXTURE AT 293, 297 AND 300 K - Mrunal M. Mahajan*1, Pravin B. Raghuwanshi2 & Mamta Mishra3 (2019)