Su Shi, Su Che and Su Xun are three father and sons. What is the relationship between the sodium salts baking soda, big soda and soda in chemistry? It turns out that they are three chemicals with different properties.
Three fathers and sons in chemistry: soda, baking soda and big soda, what are their respective abilities? Soda
The chemical composition of soda is sodium carbonate. Sodium carbonate (Na2CO3) is also called soda ash or soda ash.
Hydrated sodium carbonate with crystal water is called hydrated sodium carbonate, including sodium carbonate monohydrate (Na2CO3·H2O), sodium carbonate heptahydrate (Na2CO3·7H2O) and sodium carbonate decahydrate (Na2CO3·10H2O).
Anhydrous sodium carbonate is a white powder, easily soluble in water, and the aqueous solution is alkaline. It is highly hygroscopic and can absorb moisture in the air and form hard lumps. Sodium carbonate decahydrate is a colorless crystal. When placed in the air at room temperature, it will lose crystal water and become sodium carbonate monohydrate. Both sodium carbonate decahydrate and sodium carbonate monohydrate will turn into anhydrous sodium carbonate when heated. Sodium carbonate is very stable and does not decompose easily when heated.
Can release carbon dioxide when encountering acid:
Na2CO3+2HCl=2NaCl+H2O+CO2↑, compared to the reaction between baking soda and acid, the reaction speed is slower;
Can react with CaCl2 solution:
Na2CO3+CaCl2=CaCO3↓+2NaCl
In chemical plants, people pass carbon dioxide into the aqueous solution of soda to make baking soda:
Na2CO3+CO2+H2O=2NaHCO3.
Among the three types of soda, sodium carbonate is the most widely used. As a basic chemical raw material, soda ash is widely used in medicine (medically used to treat hyperacidity), papermaking, metallurgy, glass, soap, textile, petroleum, dyes and other industries. Soda also has many uses in daily life. For example, it can be used directly as a detergent. Adding some soda when steaming steamed buns can neutralize the acidic substances produced during the fermentation process.
Three fathers and sons in chemistry: soda, baking soda and big soda, what are their respective abilities? Baking soda
Baking soda is the common name for sodium bicarbonate, namely sodium bicarbonate (NaHCO3), which is white and fine. The solubility of crystal pinacol diborate in water is less than that of sodium carbonate, and sodium bicarbonate is weakly alkaline when dissolved in water.
Sodium bicarbonate can react with acid:
NaHCO3+HCl=NaCl+CO2↑+H2O, the reaction is rapid.
Reaction with alkali, such as reaction with NaOH:
NaHCO3+NaOH= Na₂CO3+ H2O
Reaction with calcium hydroxide: The dosage of sodium bicarbonate should be divided into small amounts and overdose.
A small amount:
Ca(OH)2+ NaHCO3= CaCO3↓+ NaOH + H2O
Excess:
Ca(OH) 2+ 2NaHCO3= Na₂CO3+ CaCO3↓+ 2H2O
Sodium bicarbonate does not react with CaCl2 solution.
Sodium bicarbonate is unstable, and the solid begins to decompose gradually above 50℃: 2NaHCO3=(△)Na2CO3+H2O+CO2↑
Double hydrolysis occurs when encountering Al3+:
Al3++ 3HCO3-= Al(OH)3↓+3CO2↑
Sodium bicarbonate has a wide range of uses. It can be directly used as a raw material in the pharmaceutical industry to treat hyperacidity. It can also be used in film production, tanning, mineral processing, smelting, metal heat treatment, and in the fiber and rubber industries. One of the most widely used loosening agents in the food industry. It is used to produce biscuits, pastries, steamed buns, bread, etc. It is a carbon dioxide generator in soda drinks. It can be compounded with alum to form alkaline fermentation powder, and can also be compounded with soda ash for civilian use. Stone soda; also used as butter preservative. Used in fire-fighting equipment to produce acid-base fire extinguishing agents and foam fire-extinguishing agents. In the rubber industry, it is used in combination with alum and H pore-forming agent to evenly create pores for the production of rubber and sponge. In the metallurgical industry, it is used as a flux for casting steel ingots. In the machinery industry, it is used as a molding aid for cast steel (sand foundry) sand molds. In the printing and dyeing industry, it is used as a fixing agent for dyeing and printing, an acid-base buffering agent, and a post-processing agent for fabric dyeing and finishing. Adding baking soda to dyeing can prevent yarn tubes from developing color blooms. In the pharmaceutical industry, it is used as raw material for antacids.
Three fathers and sons in the field of aluminum and magnesium carbonate chemistry: soda, baking soda and big soda. What are their respective abilities? Big soda
Big soda is the common name of sodium thiosulfate (Na2S2O3·5H2O), also known as “Sea Soda” “Wave”, soda is a colorless and transparent crystal with weak alkalinity, easily soluble in water, but not easily soluble in alcohol.
It is commonly used in industry to boil sodium sulfite and sulfur to obtain sodium thiosulfate, which is refined by recrystallization:
Na2SO3+ S + 5H2O = Na2S2O3·5H2O
It In dry air above 33℃, it will weather and lose crystal water. It is relatively stable in neutral and alkaline solutions, and will decompose quickly in acidic solutions:
Na2S2O3+2HCl=2NaCl+H2O+S↓+SO2↑
Big soda has very It has strong complexing ability and can form complexes with silver bromide. Reaction formula:
AgBr+2Na2S2O3=NaBr+Na3 [Ag(S2O3)2]. Based on this property, it can be used as a fixing agent. During phase washing, excess baking soda reacts with the silver bromide in the unsensitized part of the film and converts it into soluble Na3 [Ag(S2O3)2]. The AgBr is removed and the developed part is fixed.
Baking soda also has strong reducing properties and can reduce chlorine and other substances. Na2S2O3+4Cl2+5H2O=H2SO4+2NaCl+6HCl, so it can be used as a dechlorination agent after bleaching cotton fabrics. In a similar way, iodine stains on fabrics can also be removed with it.
In addition, soda is also used for tanning leather, electroplating and extracting silver from ores.
