The dissociation constant of Acridine and p-nitroanaline from 20°C to 50°C’ at 5°C interval in  aqueous  media  have been determined spectrophotometrically at ionic strength of 0.01 M  KNO3. A computer program, which calculate dissociation constants of mono acidic bases by treating spectrophotometric data have been developed and written in GW-BASIC. The results have been obtained for Acridine and p-nitroanaline at various temperatures. The pK, values of Acridine at 25°C and 50°C by wing 354 nm analytical wavelength, are 5.744 ± 0.008 and 5.013 ± 0.0010 while for p-nitroanaline at 25°C and 50°C are 0.999 ± 0.006 and 0.577 ± 0.01 respectively. Thermodynamic parameters i.e. Gibb's free energy AG, enthalpy AH and entropy AS are also calculated at different temperatures.    


M ANWAR ,SAEED UDDIN ,M SHARIF ,S T HUSSAIN ,