Applications of Lye or Sodium Hydroxide | Detailed Explanation

Lye or sodium hydroxide has intense alkalinity. It will completely dissociate into sodium ions and hydroxide ions after dissolving in water. It easily deteriorates into sodium carbonate in the air due to the presence of acidic oxide carbon dioxide. Besides, it can occur acid-base neutralization reactions with any proton acid. It can also occur metathesis reaction with salt solutions. What’s more, it can catalyze and cause saponification reactions. So what are the specific applications of these special features?

Applications of lye or sodium hydroxide

Lye or sodium hydroxide is preferred as a reagent for scientific experiments because it is alkaline, it can make the litmus solution blue and the phenolphthalein solution red. Besides, it is often used as a solution to absorb acidic gases, such as the toxic gas sulfur dioxide. And there are more applications listed below.

1. Producing cleaning agents

Lye or sodium hydroxide can be used to neutralize acidic substances, dissolve fats, and remove dirt. The specific principle is as follows:

-Neutralizing acidic substances: Its strong alkalinity can react with acids to produce salts and water, therefore, it can neutralize acidic substances. Acidic substances can often cause material surface corrosion, produce irritating odors, and other problems. Using it can neutralize acidic substances, and make the surface of objects neutral or alkaline, therefore, it can protect the surface from corrosion.

-Dissolving oil: It has good solubility, especially for fatty acid substances. It can react with fatty acids to form soap and make the oil form an emulsion that is easier to dissolve and clean. This is because it can occur hydrolysis reactions with ester bonds in fatty acids, and break them down into sodium salts and glycerol with better solubility.

-Remove dirt: It can break the chemical bonds on the surface of dirt, causing it to break and detach from the surface of the cleaned objects. At the same time, its high solubility can also dissolve dirt, making it easy to clean.

 2. Water treatment

Lye or sodium hydroxide solution is usually used in the process of sewage treatment,  it can reduce the hardness of the sewage. Besides, it is used as a measure of solubility in wastewater treatment. Because many heavy metal ions cannot dissolve in their solution, people can use this characteristic to remove most of the heavy metal ions in wastewater.

 3. Making paper

The principle of caustic soda pulping is to use wood as raw material, dissolve hemicellulose and lignin in wood fibers through lye or sodium hydroxide, and separate them. It can also cause wood fibers to aggregate and form larger chemical fiber bundles. These fiber bundles are then processed to produce high-quality paper products.

Is it harmful to the human body?

Lye or sodium hydroxide itself does not have toxicity, but due to its corrosive and irritating features, you must take protective measures such as wearing masks and gloves when using it.

If it is accidentally brought into contact with the skin, its components will quickly absorb local skin moisture, penetrate the cell membrane, bind with plasma proteins, and lead to local tissue liquefaction necrosis.

When it dissolves in water or encounters water vapor, it will release heat and form a corrosive solution. If you accidentally inhale its dust or smoke, it may enter the human body through the digestive tract, corrode the digestive and respiratory tracts, and lead to mucosal ulcers and bleeding. If the dosage is very small, after entering the stomach, it combines with the stomach acid to form sodium chloride. If these situations do not occur after drinking water, you can temporarily ignore them and continue to observe.

Storage method of lye or sodium hydroxide

lye or sodium hydroxide is a common chemical reagent used in many fields. However, due to its strong alkalinity and corrosiveness, you must follow the crucial storage conditions to ensure its safety and stability.

High temperatures and humid environments can cause the evaporation and absorption of water in its solutions, thus, it will affect its concentration and quality. Therefore, it is best to be stored in a sealed container to prevent moisture and carbon dioxide from entering the air.

Besides, it should be kept away from flammable and explosive materials. Because of the strong alkalinity, it reacts with acidic substances to generate a large amount of heat and gas, and cause fires and explosions.

Conclusion

This article mainly talks about the features and applications of Lye or sodium hydroxide. People use it to produce cleaning agents like soaps, to do water treatment, to make paper, etc. It doesn’t have toxicity, but if you breathe in its power or smoke, you should get medical help ASAP. And you should follow the strict conditions to ensure its safety.