Quantum chemical calculations within the "GAUSSIAN 09" program were employed to evaluate physical and chemical properties of selected aldehyde and diol molecules, and to elucidate the energy and the most stable geometry of their interaction. Through this, the contribution of hydrogen bonds to their reactivity was determined for 20 reaction complexes using the B3LYP (Becke, 3-parameter, Lee-Yang-Parr) Density Functional Theory (DFT) hybrid functional with the standard 6-31+G(d) basis set. Additionally, the contribution of hydrogen bonds to their reactivity was determined for 20 reaction complexes using Density Functional Theory (DFT) with the B3LYP (Becke, 3-parameter, Lee-Yang-Parr Hybrid Functionals) functional and the standard 6-31+G(d) basis set. By examining reactants in an aqueous solution, it was established that diols adopt a structure with an intramolecular hydrogen bond between the OH groups, which is also maintained in complexes with aldehydes. Analysis of various complexes revealed that systems with a single hydrogen bond are more stable than those with two, a phenomenon linked to the more favorable hydrogen bonding between hydroxyl groups compared to that between hydroxyl and carbonyl groups. Examination of multiple aldehyde and diol molecules indicated optimal hydrogen bonds with favorable distances and angles. However, the formation of reaction complexes is an endergonic process, requiring an input of energy to establish this interaction. This energy is influenced not only by electronic properties but also by the steric requirements of both reactants. Lastly, the connection between the capacity to form hydrogen bonds and the success of the conversion of aldehydes and diols into cyclic acetals and water molecules was considered.