(solved) need help making a napalm like explosive

I'm trying to make a molotov cocktail, but I can't get it burst into flame upon hitting a target, I've tried using a fill command to fill an area with fire and tried to make a flammable fluid, but the command crashed the game, and I couldn't make the fluid flammable, nor could I determine if an adjacent block was fire.

I ended up tweaking the 'flammable liquid' idea and past me was just bad, I dont know what was causing the game to crash or what I was going on about not being able to determine if an adjacent block was fire but its working now.