In order to characterize acid-base properties of a material surface under gas-phase reaction conditions, a new test reaction has been investigated. We have shown that 2-methyl-3-butyn-2-oĺundergoes dehydration over solid acid materials and gives acetone and acetylene over solid basic materials. These reactions are very sensitive to the usual modifications that can occur during catalyst preparation. Production of 3-hydroxy-3-methyl-2-butanone seems to be characteristic of amphoteric catalysts possessing acid-base ion pairs.