Short Answer
Bases are substances that show certain clear and common behaviours known as their general properties. They release hydroxide ions (OH⁻) in water, have a bitter taste, and feel soapy or slippery when touched. These properties help us identify whether a substance is basic in nature.
Bases also turn red litmus paper blue and react with acids to form salt and water, a process called neutralisation. Many bases conduct electricity in water because they contain ions. These general features make bases useful in cleaning products, medicines, and different industries.
Detailed Explanation :
General Properties of Bases
Bases are an important group of chemical substances that show several characteristic behaviours. These behaviours are called the general properties of bases, and they help us identify basic substances in daily life and laboratories. Bases are found in many common materials such as soaps, detergents, baking soda, toothpastes, and household cleaning agents. Some bases are strong and corrosive, while others are mild and safe to use. Despite these differences, their general properties remain similar.
Bitter Taste
One of the most common features of bases is their bitter taste. Substances like baking soda and certain medicines taste bitter because they contain mild bases. However, laboratory bases should never be tasted, as many strong bases are harmful and corrosive. The bitter taste is only a natural characteristic of weak, edible bases.
Soapy or Slippery Touch
Bases feel soapy or slippery when touched. This happens because bases react with the natural oils on our skin to form soap-like substances, giving a slippery feeling. For example, soap itself is basic in nature, which is why it feels smooth and slippery. This property helps us easily recognise basic solutions in everyday life.
Release of Hydroxide Ions
A base releases hydroxide ions (OH⁻) when dissolved in water. These ions are responsible for the basic nature of the substance. According to the Arrhenius concept, any substance that increases the concentration of hydroxide ions in water is called a base. For example, sodium hydroxide (NaOH) dissolves in water to release Na⁺ and OH⁻ ions. The more hydroxide ions a base releases, the stronger it is.
Effect on Litmus Paper
Bases show a clear and noticeable effect on indicators. They turn red litmus paper blue, which is a simple and widely used test to check the presence of a base. Other indicators like phenolphthalein turn pink in the presence of bases. This colour change helps students and scientists quickly identify basic substances without any complex equipment.
Reaction with Acids
One of the most important properties of bases is their reaction with acids. When a base reacts with an acid, they neutralise each other to form salt and water. This is called a neutralisation reaction. For example:
Hydrochloric acid + Sodium hydroxide → Sodium chloride + Water
This reaction is extremely useful because it helps balance excess acidity or basicity in various situations. Neutralisation is used in making medicines, treating soil, manufacturing salts, and reducing acid effects on the environment.
Reaction with Ammonium Salts
Bases react with ammonium salts to produce ammonia gas, salt, and water. This property is used in laboratories to test for ammonium ions. For instance, when sodium hydroxide is heated with ammonium chloride, ammonia gas is released, which has a distinct sharp smell.
Electrical Conductivity
Bases conduct electricity when dissolved in water. This happens because they release ions that allow the electric current to pass through the solution. Strong bases like sodium hydroxide and potassium hydroxide conduct electricity very well, while weak bases conduct less efficiently. This property is useful in various industrial processes involving electricity.
Corrosive Nature
Some strong bases are corrosive and can cause burns or damage materials. Sodium hydroxide and potassium hydroxide are examples of corrosive bases. They must be handled with care using gloves and protective equipment. However, weak bases such as baking soda and magnesium hydroxide are safe and used commonly in daily life.
Presence in Nature and Industry
Bases are found naturally in substances like plant ashes, limestone, and some minerals. Many bases are also produced artificially for industrial purposes. Bases are used in making soap, detergents, paper, textiles, bleaching agents, medicines, and many other products. Their ability to neutralise acids and react with different substances makes them extremely important in science and technology.
Conclusion
The general properties of bases include bitter taste, slippery touch, release of hydroxide ions in water, turning red litmus blue, reacting with acids to form salt and water, producing ammonia with ammonium salts, conducting electricity, and showing corrosive behaviour in the case of strong bases. These properties help us easily recognise bases and understand how they behave in daily life, nature, and industries. Knowing these properties also teaches us how to safely use bases and apply them in different fields.