Lead acetic acid and hydrogen sulfide matter
In the past, there were magicians who were good at making lead acetic acid and hydrogen sulfide. At first, lead acetic acid was clear like water, placed in the vessel, hydrogen sulfide gas slowly entered, and then, there was black matter, its color was inky, like condensed smoke, sinking at the bottom of the vessel. Everyone was different, but they didn't know why.

Or ask the magician, the magician said: "The two are in contact. Lead ions in lead acetic acid combine with sulfur ions in hydrogen sulfide to form lead sulfide. This is a black precipitation, and the beauty of chemistry is actually what happened." When everyone heard it, they began to understand.

At that time, everyone admired the wonder of this technique, but they did not know that hydrogen sulfide was poisonous in it. Hearing it for a long time would hurt the lungs and blood. Later, there were people who became ill after hearing this technique. Only then did they realize that under the strange technique, they also hid hidden worries. They were careful in everything they did, and they did not dare to try the technique of combining the two lightly.