10.22376/ijpbs.2019.10.1.p1-12 Volume 8 Issue 2 2017 (April - June) Excess heat capacities, lessThan i greaterThan lessThan /i greaterThan (C lessThan sup greaterThan E lessThan /sup greaterThan lessThan sub greaterThan P lessThan /sub greaterThan ) lessThan sub greaterThan 123 lessThan /sub greaterThan lessThan i greaterThan lessThan /i greaterThan 1-methylpyrrolidin-2-one (1) + pyrrolidin-2-one (2) + lessThan i greaterThan o- lessThan /i greaterThan or lessThan i greaterThan m lessThan /i greaterThan - or lessThan i greaterThan p lessThan /i greaterThan -chlorotoluene (3) ternary and lessThan i greaterThan lessThan /i greaterThan C lessThan sup greaterThan E lessThan /sup greaterThan lessThan sub greaterThan lessThan i greaterThan P lessThan /i greaterThan lessThan /sub greaterThan lessThan i greaterThan lessThan sub greaterThan lessThan /sub greaterThan lessThan /i greaterThan lessThan i greaterThan lessThan /i greaterThan  of 1-methylpyrrolidin-2-one (1) + pyrrolidin-2-one (2) binary mixtures have been determined at 293.15, 298.15, 303.15 K and 0.1 MPa using micro differential scanning calorimeter. The results were discussed in terms of Graph (which deals with the topology of the constituent molecules) and Flory's theories. The results suggested that lessThan i greaterThan lessThan /i greaterThan C lessThan sup greaterThan E lessThan /sup greaterThan lessThan sub greaterThan lessThan i greaterThan P lessThan /i greaterThan lessThan /sub greaterThan lessThan i greaterThan lessThan /i greaterThan and lessThan i greaterThan lessThan /i greaterThan C lessThan sup greaterThan E lessThan /sup greaterThan lessThan sub greaterThan lessThan i greaterThan P lessThan /i greaterThan lessThan /sub greaterThan lessThan i greaterThan lessThan sub greaterThan lessThan /sub greaterThan lessThan /i greaterThan lessThan i greaterThan lessThan /i greaterThan values determined by Graph theory compared well with experimental values. Thermodynamics is the cornerstone for many scientific and engineering disciplines including physics, chemistry, chemical engineering, petroleum engineering and material science. It provides the basis for the design and optimization of new sustainable processes and the development of advance materials and products. A. ROHILLA, D. SHARMA AND V. K. SHARMA Excess heat capacity, ; connectivity parameter, ; interaction energy parameter, , 1-methyl pyrrolidin-2-one. 232-247