Why did ancient people test poison with silver needles?

The most important type of poison in ancient times is arsenic that we commonly see in TV dramas, in fact, the toxic substances in arsenic itself cannot be detected with silver needles.

However, due to technical limitations, arsenic was not pure at that time, and it would be mixed with sulfur and sulfide, which would react with the silver needle and make the silver needle black, which could be verified to be toxic in the dish.

Therefore, the poison detected by the silver needle may only be poisons containing sulfur and sulfide, and most of the others cannot be detected.

I also know a home remedy, when the eyes are uncomfortable, use a boiled egg, peel it and stuff it into the silver, roll it on the eyes for a while, and then you will see a layer of black on the silver, which means that the poisonous gas in the eyes has been sucked out.

I saw my grandmother like this, and her silver bracelet did have a layer of black on it, and I thought it was amazing at the time. Now I know that the egg yolk contains sulfide that makes the silver black, and it has nothing to do with the inhalation of poisonous gas.

Brain to make up, in the TV series, the emperor used silver chopsticks to eat the egg yolk (I don't care why he used chopsticks to hold the egg yolk), suddenly the chopsticks were black, and then he was terrified, save the driver, the egg is poisonous. Isn't that interesting?

The chemical principle of the ancients' "silver needle test poison":In ancient times, when people talked about highly toxic things, they basically referred to arsenic, and the reason why it became a poison commonly used by the ancients was mainly because the acquisition of arsenic was relatively simple, and its raw materials existed in a large number of ores, and only a simple process was needed to extract arsenic from ores.

The rough refining method of the ancients made the purity of arsenic not high, even if it was white arsenic, it still contained a lot of sulfur or sulfide, and the sulfide would undergo a chemical reaction when it encountered silver to produce black silver sulfide. Therefore, once the silver needle touches the arsenic, the surface will turn black, and it can be judged whether the food contains toxicity.

Silver cannot be tested for poison, but it can be disinfectedAs little as 1 milligram of silver ions per liter of water can kill most bacteria in water. The principle is that silver can form positively charged ions in water, which can adsorb bacteria in water and gradually enter the bacteria, so that its catalyst-amidium system is closed and inactivated, so that the bacteria lose their metabolic ability and die.

Therefore, it is still beneficial to use silver as bowls and chopsticks in daily life.

The above content reference: Encyclopedia - Silver Needle.

Silver needles can really detect poisons, but not all poisons. Silver is a relatively active metal, and the active metal is relatively easy to react with other substances. Therefore, the use of silver needles to detect poisons is to take advantage of the properties of silver's active metal.

Whether in ancient or modern times, the identification of toxic substances is based on chemical reactions. Toxic substances exhibit different results after a chemical reaction. The final characteristics of a toxic substance can be used to determine what it is.

Next, let's take a look at the silver needle, a way to identify toxic substances.

1. Silver is an active metal, which is relatively easy to oxidize When we observe silver in our daily life, we can see that the silver jewelry we wear often appears black. This is proof that silver is an active metal, and it is a type of metal that is relatively easy to oxidize. There are many toxic substances that corrode animals and plants by oxidation.

Therefore, it is more reliable to use the characteristic that silver is easily oxidized to detect toxic substances.

2. Silver is an active metal, which is easy to react with other substances, and there are relatively few active metals that can be refined in ancient times, and second, active metals are easy to react with other substances. Because the smelting skills of the ancients were not very superb, silver was a relatively active metal for them. Therefore, the ancients could only use the techniques they had at their disposal to identify poisonous substances, and silver was the most convenient metal they had at their disposal to detect poisonous substances.

3. There will be sulfur in silver, which can detect arsenic toxic substances Silver contains a small amount of sulfur, especially when the ancient smelting technology is not very superb, the sulfur content retained in silver will be more, and sulfur can react with arsenic in arsenic toxic substances to make silver black. Therefore, it is very reliable to use silver to detect arsenic toxic substances.

Poisons can be detected, the ancient poison generally refers to arsenic, but also arsenic trioxide, because the technology is backward in the production of sulfur or sulfide residues, silver and sulfur will produce a chemical reaction on the surface of the silver needle to generate a layer of black silver sulfide, the ancients are based on this to infer whether it is poisonous.

Only a portion of it can be detected. Because arsenic was commonly used for poisoning in ancient times, and arsenic will have a chemical reaction with silverware, but some other poisons are difficult to detect.

Yes. But the ancient poison mainly pointed to arsenic, arsenic is what we now call arsenic trioxide, and arsenic trioxide will produce a chemical reaction after contact with silver, attaching a layer of black substance "silver sulfide" to the surface. This is the principle of drug testing.

It's true. Silver needles will turn black due to chemical reactions when poisoned, but not all poisons can be tested.

In addition to silver needles, are there any other common ways to test for poison?

Categories: Education Academic Exams.

Problem description: Silver is a heavy metal, what happens if it remains in food?

Analysis: In the folk, it is widely said that silver can detect drugs. As early as the famous forensic scientist Song Ci in the Song Dynasty, there was a record of using a silver needle to perform an autopsy.

To this day, some people often use silver chopsticks to test whether food is poisonous, and there is a traditional belief that silver can detect poison, which was also cited as the criterion by forensic medical examination at that time. Can silverware really test for drugs?

The poison referred to by the ancients mainly refers to the highly toxic arsenic, that is, arsenic trioxide, and the ancient production technology is backward, resulting in arsenic accompanied by a small amount of sulfur and sulfide. The sulfur contained in it can be in contact with silver, it can cause a chemical reaction, so that the surface of the silver needle produces a layer of black "sulfur silver", to modern times, the production of arsenic technology is much more advanced than in ancient times, the refining is very pure, no longer mixed with sulfur and sulfide. Silver metal is chemically stable and does not react with arsenic under normal conditions.

It can be seen that the ancients used silver to test for poison because of historical and scientific limitations. Some items are not poisonous, but they contain a lot of sulfur, such as egg yolks, and silver needles will turn black when they go to it. On the contrary, some are very poisonous, but do not contain sulfur, such as mushrooms, nitrites, pesticides, rat poison, cyanide, etc., and silver needles will not react black when they come into contact with them.

Therefore, silver needles cannot identify poisons, let alone be used as a tool for drug testing.

Silver cannot be tested for poison, but it can be disinfectedAs little as 1 milligram of silver ions per liter of water can kill most bacteria in water. The mechanism is that silver can form positively charged ions in water, which can adsorb bacteria in water and gradually enter the bacteria, so that its catalyst-enzyme system is closed and inactivated, so that the bacteria lose their metabolic ability and die.

Therefore, it is still beneficial to use silver as bowls and chopsticks in daily life.

Ancient rumors, after all, the poison used at that time was inferior arsenic obtained after direct heating of realgar, which contained sulfur, and silver would only turn black when it touched sulfur, so it was rumored that it could be tested with silver needles, and the arsenic after modern purification could not be detected by silver needles.

Because silver is a metal with extremely stable chemical properties, it will not react with other substances under normal conditions, but silver can react with sulfur, and once the reaction occurs, the surface of silver will produce black reactants.

In ancient times, arsenic was often used as a poison, and due to technical limitations, arsenic would be mixed with a large amount of sulfur or sulfide. Silver reacts with sulfur to form a black silver sulfide precipitate, which tests for poison. It can be seen from this that the silver needle test is only the detection of sulfur in arsenic, and for the countless poisons today, the silver needle test is powerless.

The reason why there was this kind of poison detection method in ancient times is that the conditions in ancient times were limited, and the refining technology was not developed, and the arsenic produced was more or less impurities, and these impurities of course included sulfur.

There is a scientific basis for the reliability of the method of testing drugs with silver needles.

This method is very reliable for ancient people, and there is a scientific basis, because the ancient drug production technology is not so profound, and the concentration of refining is not pure enough, so there will be impurities, which can be tested through silver needles.

In ancient times, it was more reliable, because the ancient poison generally contained arsenic, because the purification technology was limited, and the sulfur in the arsenic would have a chemical reaction with the silver needle; There is a scientific basis.

This method is not particularly reliable. This method has a scientific basis, the scientific basis is not strong, and it has not been subjected to relevant experiments, so it is not worth believing.