Why ethynes are more energy producing through combustion

Ethynes possess a triple bond structure which is harder to break so when it comes in contact with oxygen it takes more energy to break the bonds thereby giving out more energy in form of CO₂ and H₂O and energy.

That result from subduction of oceanic plates beneath lighter continental plates. most of the earth's volcanoes are located around the pacific ring of fire because that the location of most of the earth's subduction zones.