Various mechanistic aspects of small-alkane transformations on strong solid acids or superacids are developed in Light of recent experiments involving isotope distribution patterns in C-13-labelled alkanes and protium/deuterium exchange between alkanes and D2O-exchanged catalysts. In comparison with experiments using liquid superacids, similarities and differences in hydrocarbon chemistry between the two types of catalysts are discussed as well as the initial steps leading to catalyst deactivation.