Hey guys and welcome back to another video. Today I will show you an interesting method of producing hydrogen sulfide gas from elemental sulfur. Before I get started I'm just going to quickly mention that hydrogen sulfide is quite toxic, so due to some of the ventilated areas, ideally a fume hood. The common methods include dripping HCl on purchased iron sulfide powder or self-made aluminum sulfide. This and iron has shown a method which uses paraffin wax to reduce the sulfur. This is however a quite messy process. His main goal was to get a reaction that can be stopped and restarted later. As you will see my method is also capable of doing this, because both reagents are liquids and instantly react. To get started I prepared a solution of sodium poly sulfide. A theory any poly sulfide can be used. Depending on whether sodium hydroxide or sulfur is more valuable to you, the mass ratio can range anywhere from one part sodium hydroxide to 0.8 up to two parts of sulfur. If the ratio is lower you will use more sodium hydroxide than theoretically needed, but you will have less chance of building longer poly sulfide chains, which may precipitate later and be difficult to clean. In the video I used a ratio of about 1.7. Some poly sulfide chains were formed at the end, but it was still quite easy to clean. After dissolving the sodium hydroxide I added the sulfur and left it stirring on the heat for about 30 minutes. As you can see the color changed to a dark red and the liquid should become crystal clear. The last few flakes of sulfur were filtered out and the solution was ready. The amount of water used also isn't too critical, but keep in mind that upon cooling you may crystalize the poly sulfides out if the solution is too concentrated. Now for the actual production of hydrogen sulfide I assembled this apparatus, using a two necked round button flask, but a clasen adapter is also a good option. Apart from that it consists of a pressure equalized addition funnel, which in my case needed an expander piece to fit the joints together. And of course a gas outlet adapter. In theory this can also be mounted on top of the addition funnel and used with a single neck flask. Now I filled the flask with hydrocloric acid and put the poly sulfide solution in the addition funnel. This way once you're done and some is left it can simply go back to storage without being contaminated with anything. Upon addition to the HCl hydrogen sulfide was evolved and the bleached solution in which the gas was let quickly turned opaque, due to the oxidation back to elemental sulfur. I can also test for its presence with some lead acetate paper, which as you can see quickly turns black. This process is very easy to control because the liquids react instantly. However it isn't the most efficient since some elemental sulfur is also produced in the reaction. Keeping the ratio of sulfur small reduces the spy product, but more HCl is needed to neutralize the hydroxide. So depending on what is more important in your circumstance, just change the ratio accordingly. The solution is also quite stable in storage. The higher the sodium hydroxide concentration the less hydrogen sulfide is evolved. To prevent the formation of long sulfur polymers it should be somewhat protected from light. That's basically it for this video. Thanks for watching.