A theoretical study of 3-(4-Chlorophenyl)-1,1-dimethylurea and its protonated isomers has been carried out, to emphasize the experimental results of the electrostatic interactions in the herbicide models, for investigating the implications taking place on the structural parameters starting from the gaseous phase to the aqueous one. It has been found that its functionalized structure gives us three protonated targets. The calculations has been performed on both neutral and protonated forms using Density Functional Theory (DFT) with the hybrid functional B3LYP. Many molecular parameters have been studied. To identify the reactive sites, our study has focused on the local and the global reactivity descriptors explaining the chemical reactivity. The calculations have demonstrated that the attacks on the aliphatic branched exocyclic positions are privileged to those of the aromatic ring. Studying the solvent effect has revealed that there is a change in the hierarchy of the electrophilicity. Various vibrational modes have been exploited to discuss the literary spectroscopic data.