Page 34 - Curriculum Visions Dynamic Book

Sodium hydroxide as a household chemical
Sapo is the Latin word for soap. Saponification therefore, means making soaps.
Saponification is a natural reaction of sodium hydroxide and any animal fat or vegetable oil. This is a most valuable reaction because it means that sodium hydroxide can be used to make soap and it can also be used in drains and other places to destroy unwanted build-up of fat or oil.
Caustic soda and water
If you put crystals of sodium hydroxide into water an immediate reaction occurs, releasing considerable amounts of heat. The heat released can bring the water close to boiling within seconds.
Making a solution of sodium hydroxide therefore creates a very hot, very strong alkaline substance, and one that must be treated with care and respect, especially as it
is commonly kept in many household cupboards.
 When sodium hydroxide crystals are added to water they create a hot, caustic solution. The picture on the left shows a beaker of water before the sodium hydroxide crystals were added. The thermometer on the right shows the temperature increase as the crystals were added. This is an exothermic reaction, i.e. it produces heat.
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