Questions about solid desiccant。。。。。

Acids such as H2SO4 and HNO3 are acids that only contain hydrogen ions and acid ions

Alkalis such as NaOH mg(OH)2, only metal ions and hydroxide ions are bases.

As for the salt. Na2CO3, which has both metal ions and acid ions, is a salt. You know acid-base neutralization, right? You can think of it this way, the acid in the acid and the metal ions in the base react into salts. That hydrogen and hydroxide are turned into water

It doesn't matter if there is hydrogen in the middle of NaHCO3, because the acid group is HCO3- or it conforms to the format of metal ions and acid ions.

If the desiccant is to have the function of absorbing water, what do you think can react with water? Well, the solid is quicklime cao. To generate calcium hydroxide, concentrated sulfuric acid is used as a liquid, which has a strong water absorption function

So much hope!! Thank you!!

Calcium chloride, calcium oxide solids, etc. can be used as desiccant, sodium hydroxide solution can also be used to dry neutral gas, and concentrated sulfuric acid can also be dried. Acid is a compound that ionizes completely hydrogen when ionized in solution and can make the purple litmus solution red, and the colorless phenolphthalein does not change color, and salt is a compound composed of acid ions and metal ions. Alkali is a compound that ionizes in solution when the anion is completely hydroxide ion and can make the purple litmus solution blue and the colorless phenolphthalein red

Acids with H+ ions, such as H2SO4, HCl, etc.

Base with OH-ions, such as NaOH Ca(OH)2, etc.

In addition to acids and bases, everything else is salt.

Alkaline desiccant: Dry alkaline gas: Alkaline gas: Alkaline gas: Alkaline gas: Alkaline desiccant: Alkaline gas: Alkaline gas, alkaline gas, alkaline gas

Desiccant is suitable for preventing instruments, meters, electrical equipment, medicines, food, textiles and other packaging items from moisture, desiccant is also widely used in shipping, because the goods are often deteriorated due to high temperature during transportation, desiccant can effectively dehumidify and prevent moisture, so that the quality of the goods can be guaranteed by blind history.

The use of desiccant is as follows:

1. Desiccant is used for moisture-proof of bottled drugs and food. Ensure the dryness of the contents and prevent the growth of various miscellaneous molds;

2. The drying agent can be used as a general packaging desiccant for moisture-proof;

3. The desiccant can be easily placed in the grinding packaging of various items, such as instruments, electronic products, leather, shoes, clothing, food, medicine and household appliances, etc., to prevent the items from being damp, mildewy or rusty.

Precautions for using desiccant.

1. When using, the desiccant should be put in a bag or box with the protected items, and it is recommended to seal and store the protected items for better use effect.

2. It is best not to expose the unused desiccant to the air for more than 2 hours, and it should be sealed and stored for later use.

3. The amount of desiccant is recommended to be selected according to not less than 2000 grams of desiccant per square meter. Here you can refer to the conditions (humidity or temperature) of the storage items in the space of the product you are protecting, as well as the tightness of the desiccant packaging material.

4. Although desiccant is a relatively environmentally friendly, safe and non-toxic product, any desiccant is inedible and cannot be eaten by mistake. Keep out of reach of children. Do not tear the desiccant bag and remove the desiccant, and the bag should not be used for other purposes.

To prevent misuse, keep away from food and drinks. If the desiccant is ingested by mistake, it is generally fine to drink water to dilute it, and if necessary, send it to the hospital for further treatment.

The properties and uses of commonly used desiccants are as follows:

1. Concentrated H2SO4: It has strong water absorption and is commonly used to remove water from gases that do not react with H2SO4. For example, it is often used as a desiccant for H2, O2, CO, SO2, N2, HCl, CH4, CO2, Cl2 and other gases.

2. Anhydrous calcium chloride: It is widely used because of its low price and strong drying ability. The drying speed is fast, it can be regenerated, and the dehydration temperature is 473K.

It is generally used to fill dryers and drying towers, dry chemicals and a variety of gases. It cannot be used to dry ammonia, alcohol, amines, acyls, ketones, aldehydes, esters, etc.

3. Anhydrous magnesium sulfate: It has a strong drying ability and is generated after water absorption. Rapid water absorption, high efficiency, low price, is a good desiccant. It is often used to dry organic reagents.

4. Solid sodium hydroxide and alkali lime: fast water absorption, high efficiency, cheap, excellent desiccant, but can not be used to dry acidic substances. The party is used to dry gases such as hydrogen, oxygen, ammonia, and methane.

5. Color-changing silica gel: commonly used to keep instruments and balances dry. It turns red after absorbing water. Failed silica gel can be dried and regenerated before reuse. It can be dried amine, NH3,

O2, N2, etc.

6. Activated alumina (Al2O3): large water absorption, fast drying speed, and regeneration (400

500k bake).

7. Anhydrous sodium sulfate: the drying temperature must be controlled within 30, and the dryness is worse than that of anhydrous magnesium sulfate.

8. Calcium sulfate: can dry H2

co、n2cl2、hcl

h2s、nh3、

ch4, etc. From the above, it can be seen that the desiccant for some gases can be selected as follows.

The name of the gas. Commonly used desiccant.

The name of the gas. Commonly used desiccant.

Co concentrated H2SO4, CaCl2, P2O5

h2scacl2

CO2CaCl2, concentrated H2SO4, P2O5

N2 concentrated H2SO4, CaCl2, P2O5

Cl2CaCl2, concentrated H2SO4

NH3CAO, KOH or soda lime.

h2cacl2、p2o5

noca(no3)2

hbrcabr2、znbr2、o3

CaCl2HclCaCl2, concentrated H2SO4

SO2, concentrated H2SO4, CaCl2, P2O5

hicai2

No**.

The desiccant in it is mainly silica gel, and after the silica gel is added to water, it will make a sound because of the uneven local water absorption, and it will expand unevenly and crack.

The inside of the silica gel desiccant is a very fine porous network structure, these pores can absorb water and retain the water through its physical attraction, and are widely used as a desiccant in aviation parts, computer devices, electronic products, leather products, medicine, food and other industries to dry and moisture. Even if the silica gel desiccant is fully immersed in water, it will not soften or liquefy. It is non-toxic, tasteless, non-corrosive and non-polluting, so it can be in direct contact with any item.

This is a normal reaction when the desiccant absorbs moisture, it will not be **, this can be assured!