What are Bases?

Definition:

 Bases are a group of chemical substances that exhibit specific properties when dissolved in water or other solvents. They are an essential concept in chemistry and are often contrasted with acids.

Here are some key characteristics and properties of metals:

• PH: Bases have a PH of more than 7. A PH paper determines whether a solution is basic or not.
• Bases react with Acids to make the solution Neutral.
• Bases can be determined by their Bitter Taste and Soapy touch.
• A Base may be defined as a substance capable of releasing one or more OH- ions in Aqueous solution.
• Water soluble bases are known as Alkalies.
• Bases turn the colour of red litmus paper to blue litmus paper.
• Bases which are almost completely ionised in water are known as strong Bases.

     

1. Arrhenius Bases: According to the Arrhenius theory, a base is a substance that, when dissolved in water, increases the concentration of hydroxide ions ($�{�}^{-}$) in the solution. The classic example of an Arrhenius base is sodium hydroxide ($����$).

   Arrhenius base definition: A substance that increases the concentration of hydroxide ions in an aqueous solution.

2. Bronsted-Lowry Bases: The Bronsted-Lowry theory defines a base as a substance that can accept a proton (H⁺). This definition is broader than the Arrhenius definition because it doesn't require the presence of water. In this context, a base is a species with an available pair of electrons that can form a new covalent bond by accepting a proton.

   Bronsted-Lowry base definition: A substance that can accept a proton.

3. Lewis Bases: The Lewis theory defines a base as a substance that can donate a pair of electrons. This definition is even broader than the Bronsted-Lowry definition because it doesn't necessarily involve protons. According to this theory, a base is any species (molecule or ion) that has a nonbonding pair of electrons that can be donated.

   Lewis base definition: A substance that can donate a pair of electrons.

It's important to note that these definitions of bases cover a range of substances and reactions. Some common examples of bases include hydroxides (like $����$), ammonia ($�{�}_3$), and carbonate ions ($�{�}_3^{2-}$). The strength of a base can also be classified as strong or weak, depending on how much it ionizes or dissociates in solution.