Absolutely! Hydrogen bonding plays a crucial role in stabilising the secondary and tertiary structures of proteins. The primary structure of a protein, its sequence of amino acids, can fold into regular patterns like alpha-helices or beta-pleated sheets, primarily held together by hydrogen bonds. Furthermore, in the tertiary structure, hydrogen bonds form between different parts of the polypeptide chain, contributing to the unique three-dimensional shape of the protein, which is vital for its function.

Hydrogen bonding is more specific than other types of intermolecular forces due to the particular atoms involved and the strength of the interaction. For hydrogen bonding to occur, a hydrogen atom must be covalently bonded to a highly electronegative atom (typically fluorine, oxygen, or nitrogen) and interact with another electronegative atom. This specificity results in a more directed and stronger force compared to the more generalised Van der Waals forces, which can occur between any adjacent molecules based on fleeting charge imbalances.

This intriguing phenomenon is due to hydrogen bonding in water molecules. As water cools down and begins to freeze, the molecules arrange themselves in a hexagonal pattern, forming an open and spacious lattice structure due to the angles at which hydrogen bonds hold the molecules together. This structure occupies more volume but has fewer molecules per unit space, making ice less dense than liquid water. Hence, ice floats on water. This feature is vital for aquatic ecosystems, as it ensures that bodies of water freeze from the top down, providing insulation and allowing life to persist below the icy layer.

Hydrogen bonds significantly influence the viscosity of liquids. The presence of these strong intermolecular forces requires more energy to make molecules slide past each other. As a result, liquids that exhibit extensive hydrogen bonding, like water or glycerol, have higher viscosities compared to those with similar molecular weights but weaker intermolecular forces. This enhanced viscosity is a direct result of the interconnectedness of molecules via hydrogen bonds, making it more challenging for them to move freely.

Yes, hydrogen bonds can form in non-aqueous systems, provided the necessary components for hydrogen bonding are present. For instance, pure ethanol displays hydrogen bonding as the hydroxyl (-OH) groups in one molecule can bond with those of neighbouring molecules. Additionally, in many organic reactions involving solvents other than water, hydrogen bonding can significantly influence the course and speed of the reaction due to interactions between solvents, reactants, or products.