The purpose of this research was to design a didactic unit on chemical solutions that promotes the intrinsic motivation of the tenth grade students of the Antonio Ricaurte Educational Institution of Planeta Rica Córdoba-Colombia in the learning of Natural Sciences, attending to the need to respond to the challenges in the training of students, which requires innovative, contextualized and active strategies from the teacher, which encourage them to carry out inquiry, comparison, analysis and reflections on what they learn. To do this, we worked from a mixed approach, with a methodological design that responded to projective research; supported by a documentary review to establish the criteria in the design of a didactic unit and semi-structured interviews with students. Based on the results of the documentary review and semi-structure interviews, the design of a didactic unit was carried out that allowed proposing concepts and contextualized and active activities to promote the intrinsic motivation of students in learning chemical solutions. The contribution of this work consists of designing a didactic unit as a strategy that promotes the intrinsic motivation of students in the learning of chemical solutions, allowing them to participate actively in the construction of their learning.