It needs to be vaporized and mixed with air between the upper and lower explosive limits, otherwise no boom.
I have a story about this. Some of you may have already heard this but it'll be instructional for new members.
Growing up in Minnesota my mom used to catch rain water in 5-gal buckets. One winter she never brought the buckets in so the water in them froze. For some reason I decided to dump the chunks of ice out and in doing so I discovered the water had frozen from the outside towards the middle. The ice was about 1.5" thick on the sides and maybe about 3" thick on the top and bottom. I drilled a hole in the top of one of them and poured out the unfrozen water from the center. Pondering what to do next I decided it'd be really cool to see fire burning inside of ice so I got dad's gas can and poured about an inch of gas into the hollow ice block. Thinking about the safety of this setup, I tipped the block over and rolled it about twenty feet from the house, then set it upright again.
After that, things get a little blurry. I remember lighting a match and, looking straight down over the hole, beginning to drop the match in. Suddenly I couldn't see, my hand hurt, and my ears were ringing but I could hear large "WHUNK!" sounds as chunks of ice crashed out of the sky onto our house, our car, the neighbor's car, etc...
I was only seven at the time but from that second on I knew what I wanted to do with my life.
-Blast
p.s. Kids, don't try this at home! Find a gravel pit or something like that. Make sure it has cell phone coverage and is accessible by ambulance.