When I was 12 to 18 (1942 to 1948), I was able to buy various chemicals which I assume are not available to teenagers today. I think I bought them at a pharmacy, but might have got them at chemical supply house. I used concentrated acids to make gun cotton (nitro cellulose), an explosive used in old fashioned cannons & which might be used today in more sophisticated artillery. I also made ordinary gun powder, for which the necessary chemicals might be easily available today. I could have made nitroglycerin & nitrogen chloride, but considered them too dangerous to play with. BTW: Nitrogen chloride is a dangerously volatile chemical. I think it will explode due to direct sunlight or a mild bump of the container.