Pyridine, 2-bromo-3,5-dichloro-

What are the chemical properties of this product? There is a saying in "Tiangong Kaiwu": "All things in the world have their own unique properties, whether strong or soft, dry or moist. In terms of chemical properties, they are also different."
Take metal products as an example. Gold is stable in nature and is not easy to combine with others. As the book states, "Gold enters a fire, and its color does not lose its pure light". This is the sign that gold is chemically stable and not easy to be oxidized under high temperature and strong oxidation environment. It is also difficult to react in common acids and bases, and is only soluble in aqua regia. This is because of its unique electronic structure, which makes its chemical activity very low. < Br >
The chemical properties of iron are more active than those of gold. Iron easily reacts with oxygen and water in the air and rusts. This is the oxidation process of iron, and the main component of rust is iron oxide. Although the book does not describe the chemical reaction formula of iron rust in detail, the description of "iron is left in the tide for a long time and gradually rusts" shows its susceptibility to oxidation. Iron can also react with acids. For example, iron reacts with dilute sulfuric acid to generate hydrogen and ferrous sulfate. This is because iron is located before hydrogen in the metal activity sequence, and can replace hydrogen in the acid.
Looking at non-metallic products, such as sulfur, which is flammable, and sulfur dioxide is generated when burned. " "Sulfur is yellow, its flame is blue and purple, and the gas is pungent" in Tiangong Kaiwu. This combustion reaction is the combination of sulfur and oxygen under ignition conditions, and the sulfur changes from zero valence to positive tetravalent, which fully reflects the chemical activity of sulfur. Sulfur can also react with metals to form metal sulfides, which is one of its chemical properties.
Another example is table salt, which is mainly composed of sodium chloride and has relatively stable chemical properties. At room temperature and pressure, it is not easy to react with common substances. However, under specific conditions, such as electrolytic melting of sodium chloride, metal sodium and chlorine can be formed. This is the use of the characteristics of its ionic compounds to undergo oxidation and reduction reactions under the action of electrical energy.
To sum up, the chemical properties of different products vary widely, whether they are stable or active, depending on their atomic structure, chemical bonds, and other internal factors. As "Tiangong Kaiwu" acknowledges, all things in the world have their own characteristics, and chemical properties are also an important manifestation of the characteristics of all things.

The physical properties of this product are as follows: it is firm and dense in quality, warm to the touch, like suet, pure in color, or as white as frost and snow, or as green as jasmine, without variegated stains. Its sound is clear, and it hits with objects. The sound is like jade, melodious and long, and it will last for a long time. Its specific gravity is suitable, and it is held in the palm of your hand. It has a sense of sinking, but it does not feel heavy, which is appropriate.
Looking at its shape, it may be in the shape of a natural block, round and moist, without edges and corners, just like a natural workmanship; or it may be in the shape of a stack, with delicate texture, like the pages of a book, and it is well organized. Its surface occasionally has subtle textures, like mountains and rivers, which are natural and natural, and cannot be deliberately copied by human beings.
In addition, its thermal conductivity is good. When placed in the hand, it is slightly cool at first, but after a while, it will be in harmony with body temperature, and the warmth will gradually emerge. And it has a certain toughness. Although it is not indestructible, it is difficult to crack it due to ordinary collisions. This is all due to the remarkable physical properties of this product, which is actually given by heaven, which is especially rare.

This product is widely used and has applications in many fields.
In the field of agriculture, its help is quite great. It can be used in farmland irrigation systems to precisely control water flow to ensure that crops get the right amount of water, just like a god-given rain, nourishing crop growth. Whether it is farmland in vast plains or mountain terraces, it can play its role, helping farmers reduce irrigation efforts and improve irrigation efficiency, so that crops can thrive and harvest can be expected.
In the workshop, it is also indispensable. In the machine manufacturing workshop, it can be used as a delicate component to help the precise operation of the equipment. On the construction site, it can be used to build a stable structure, support the building body like a beam, ensure the smooth progress of the project, and make it more convenient and efficient for craftsmen to build houses and buildings.
In the place of military battle, it also has its place. It can provide assistance for marching, such as building temporary fortifications, consolidating defenses, and giving soldiers more security on the battlefield; it can also be used to make special equipment to help march and enhance the combat effectiveness of the army.
In the life of the market, it can also be seen everywhere. In the store, it can be used to display goods, cleverly arrange shelves, and attract customers' attention; in the home of ordinary people, it can be used to repair homes, create practical utensils, and add convenience to life.
In short, this product plays an important role in many fields such as agriculture, industry, the military, and the people, and contributes an indispensable force to the development of all walks of life and the convenience of people's lives.

There is a thing today, I want to know how to make it. Why this thing is, although it is not explicitly stated, it should be made with ancient law and fine art.
Ancient utensils must first understand their use, examine their shape, and measure their materials. Examine their needs, and then find good craftsmen and craftsmen. When choosing materials, make sure to choose their essence, and those with high quality and stable properties are the best. Wood is selected with meticulous texture, firm and durable; gold is selected for its purity, softness and rigidity.
At the beginning of the making of utensils, planning is the first. The craftsman uses his ingenuity, paints its shape on plain paper, determines its size, and details its structure. Between the milliseconds, it is all about the success or failure of the utensils. Every twist, every arc, must be carefully designed, so as to have both form and spirit, both practical and beautiful.
As for the craftsmanship, follow the ancient method and be meticulous. Chop wood with axes and catties, transport catties into the wind, cut like mud, so that the shape of the wood is gradually formed; cast gold with a furnace, blazing fire, turning gold into liquid, pouring into the fan, waiting for it to condense, and then applying the work of grinding. The art of carving is also indispensable. The knife is used as a pen to engrave patterns on the utensils, or for the show of mountains and rivers, or for the spirit of birds and beasts, or for the picture of auspiciousness, giving the utensils a cultural heritage.
In the meantime, the mastery of the fire is particularly crucial. If the fire is fierce, the material will be destroyed, and if the fire is small, the work will be difficult to achieve. The craftsman, based on his experience, observes the fire, observes the material changes, and adjusts it in a timely manner to make the utensils suitable. And in the process of making utensils, multiple processes often need to cooperate with each other, orderly in sequence, and not disordered.
After all the craftsmanship is completed, it still needs to be modified. Painting is warm in color, which not only protects the utensils, but also increases their elegance; inlay is dazzling and adds its luxury.
In general, the way to make this thing lies in clear use, material selection, planning, fine craftsmanship, and adapting to fire, and each link complements each other to form a delicate utensils.

There is a product today, its safety precautions are very important, and it should be paid attention to in detail.
First, it concerns the use environment. This product should be placed in a dry and ventilated place, and must not be used in a humid or sultry place. If it is in a humid place, water vapor is easy to seep into it, damaging its components, causing circuit failure, malfunction in the light, or the risk of short-circuit fire in the heavy; and a sultry environment is unfavorable for heat dissipation, causing components to overheat and reducing their lifespan.
For the second time, the operating specifications must not be ignored. Read the manual carefully before use and follow the steps shown in it. If it is not operated properly, such as excessive force or misconnection of the circuit, it can damage the product, or even endanger personal safety. And when operating, hands must be dry to prevent electric shock.
In addition, product maintenance is also the key. Regular cleaning to remove dust can ensure its stable performance. When cleaning, use a soft and clean cloth, wipe the surface lightly, and do not use sharp objects to avoid scratches. If you see any abnormalities such as loose parts or abnormal noises, you should immediately stop the machine for inspection, do not use it forcibly, and quickly seek professional maintenance.
In addition, when storing, keep away from fire sources, water sources and strong magnetic fields. Fire sources can easily cause products to catch fire and burn; water sources are accidentally soaked, the consequences are unimaginable; strong magnetic fields may interfere with their internal electronic components, messing with their operation logic.
All these safety precautions are related to the normal use and personal safety of the product. They must be kept in mind and implemented effectively to ensure safety.