Answer:
If the flammable limit of carbon monoxide is 12.5, and it is five times greater than the flammable limit of acetylene, we can calculate the flammable limit of acetylene as follows:
Flammable limit of acetylene = Flammable limit of carbon monoxide / 5
Flammable limit of acetylene = 12.5 / 5
Flammable limit of acetylene = 2.5
Therefore, the flammable limit of acetylene would be 2.5.