Sodium hydroxide

This white solid is very strong.

It can clean out clogged drains. It also helps make soap.

When it touches skin, it feels slippery. This is because it turns skin oils into soap.

It can cause bad burns. We must be very careful with it.

It can even help clean drinking water. It is used in many big jobs.

Sodium hydroxide is a white solid. It is also called lye or caustic soda.

People use it in many ways. It helps make paper and soap. It is even used to clean drinking water. In 2022, the world made 83 million tons of it.

This substance is a strong base. A base is a type of chemical. It can be very harsh. It can cause bad chemical burns on skin.

If it touches your skin, it feels slippery. This happens because it turns skin oils into soap. This set of steps is called saponification.

Sodium hydroxide likes to mix with water. When you add it to water, it gets very hot. This is called an exothermic reaction.

You must be careful not to splash the liquid. It can also soak up gas from the air. It is used to clean out clogged drains. It can also help clean harmful gases from the air.

Sodium hydroxide is a white solid that people often call lye or caustic soda. It is an inorganic compound, which means it is not made from living things. This substance is a very strong base. A base is a type of chemical that can react with acids. Because it is so strong, it is also called highly corrosive. This means it can break down things like proteins and fats very quickly.

If it touches your skin, it can cause severe chemical burns. It is a very important tool in many different industries around the world.

There are many ways this chemical works in science and industry. When you mix solid sodium hydroxide with water, it creates an exothermic reaction. This means the process releases a large amount of heat. You must be careful because the heat could cause the liquid to splash.

The liquid feels slippery if it touches your skin. This happens because of a process called saponification. In this process, the chemical turns the natural oils on your skin into soap. It also works to clean out clogged drains and helps make paper and textiles.

In the past, people used a different way to make this substance. They used a method called causticizing. This involved treating sodium carbonate with calcium hydroxide. They used this because sodium hydroxide dissolves in water, but calcium carbonate does not. Later, a new way called the chloralkali process was found. This modern method is much faster because it produces the chemical in a single step. Today, most sodium hydroxide is made using this electrolytic process. It also creates chlorine gas as a byproduct.

There are many interesting numbers and facts about how much we use. In the year 2022, the world produced about 83 million dry tonnes of sodium hydroxide. This is a huge amount compared to 45 million tonnes produced in 1998. North America and Asia each produced about 14 million tonnes. Europe produced about 10 million tonnes. In the United States, a company named Olin is a major producer. They make about 5.7 million tonnes every year at many different sites.

You can see how this chemical works by looking at other things you know. For example, it can react with acids to make water and salt. If you mix it with hydrochloric acid, it creates sodium chloride. This is the same thing as common table salt.

It can also react with harmful gases like sulfur dioxide. This helps "scrub" or clean the air by removing bad gases from coal burning. It even helps treat drinking water by using aluminium hydroxide to filter out tiny bits of dirt. This makes the water much cleaner for people to use.

Sodium hydroxide is an inorganic compound with the chemical formula NaOH. It is also commonly known by the names lye or caustic soda. This substance is a white, solid ionic compound made of sodium cations and hydroxide anions. It is categorized as a highly corrosive base and an alkali. Because it is so reactive, it can decompose lipids, which are fats, and proteins at room temperature. This property makes it useful in many industries, but it also means it can cause severe chemical burns at high concentrations.

The way sodium hydroxide behaves in water is quite intense. When you dissolve solid sodium hydroxide in water, it undergoes a highly exothermic reaction. This means the process releases a large amount of heat. This heat release can be a safety threat because it might cause the liquid to splash. The resulting solution is usually colorless and has no smell. A 50% aqueous solution has a specific viscosity, or thickness, of 78 mPa·s. This is much thicker than pure water, which has a viscosity of only 1.0 mPa·s. In fact, it is nearly as thick as olive oil, which has a viscosity of 85 mPa·s.

Sodium hydroxide can exist in several different forms called hydrates. A hydrate is a compound that contains water molecules within its crystal structure. Spencer Umfreville Pickering described these complex solubility patterns in 1893. There are many known hydrates, such as the heptahydrate, pentahydrate, and tetrahydrate. The monohydrate, which is NaOH·H2O, is very common. In fact, much of the sodium hydroxide sold commercially is actually this monohydrate form. The monohydrate crystallizes from water solutions at temperatures between 12.3 and 61.8 °C.

Chemical reactions allow sodium hydroxide to perform many different tasks. When it reacts with a protic acid, it performs a neutralization reaction. This process produces water and a corresponding salt. For example, reacting sodium hydroxide with hydrochloric acid produces sodium chloride, which is common table salt. This reaction is also exothermic, meaning it releases heat. Sodium hydroxide can also react with acidic oxides like sulfur dioxide. This is used to "scrub" or clean harmful gases from the air produced by burning coal.

In industrial settings, sodium hydroxide is used for a variety of specialized purposes. It is used in the production of wood pulp, paper, and textiles. It is also used to treat drinking water and to make soaps and detergents. In one water treatment process, sodium hydroxide reacts with aluminum sulfate to create aluminum hydroxide. This substance acts as a gelatinous flocculant, which helps filter out tiny particles from the water. Additionally, it is a common ingredient in many drain cleaners.

One interesting chemical process involving sodium hydroxide is saponification. This is the base-driven hydrolysis of esters. If sodium hydroxide touches bare skin, it creates a slippery feeling. This happens because the chemical converts the natural oils on your skin, such as sebum, into soap. While it is useful for making soap, the chemical is also quite aggressive toward other materials. It can react with glass to form soluble silicates, which can cause glass joints to "freeze" or stick together. It can even react with aluminum to produce hydrogen gas, which can cause pressure to build up in containers.

The production of sodium hydroxide has changed significantly over time. In the early 19th century, people used the causticizing process. This involved treating sodium carbonate with calcium hydroxide. This worked because sodium hydroxide is soluble in water while calcium carbonate is not. Today, most sodium hydroxide is made through the electrolytic chloralkali process. This modern method produces sodium hydroxide in a single step and creates chlorine gas as a byproduct. Global production has grown massively over the years. In 1998, world production was about 45 million tonnes. By 2022, worldwide production reached approximately 83 million tons.