Applying fractional cohesion parameters to calculate the enthalpies of chemical denaturation revealed the forces affecting this process. We applied Hansen's concept of three-component fractional cohesive parameters to consider the influences of the dispersion or non-polar interaction, the hydrogen bonding, and the polar interaction in the analysis of the chemical denaturation of DNA. with different roles. This issue has been explained in terms of Lewis acid-base cohesion parameters. The relationship among these parameters is the following: