↓Answer↓
What is a Base?
The ionic compounds that produce negative hydroxide (OH−) ions when dissolved in water are called bases. A compound containing negative nonmetal ion as well as a positive metal ion that is held together by the ionic bond is called an ionic compound.
But what are ions? Ions are atoms which become charged particles as a result of losing or gaining electrons. NaOH (sodium hydroxide) is an example of a base. When it dissolves in water, it generates negative hydroxide (OH−) ions and positive sodium (Na+) ions. It can be represented by the following equation:
NaOH →H2O + OH− + Na+
Types of Bases
- Strong base – It is a compound that has an ability to remove a proton from a very weak acid. Or they completely dissociate into its ions when in water. Examples are potassium hydroxide (KOH), sodium hydroxide (NaOH).
- Weak base – There is incomplete dissociation when in water. The aqueous solution contains both the weak base as well as its conjugate acid. Examples are ammonia (NH3), water (H2O), pyridine (C5H5N).
- Superbase – These bases are better at deprotonation when compared to a strong base. These have very weak conjugate acids. They can be obtained by mixing an alkali metal with its conjugate acid. It can’t sustain in aqueous solution as it is a stronger base than hydroxide ion. Examples are sodium hydride (NaH), ortho-diethynylbenzene dianion (C6H4(C2)2)2−
- Neutral base – It forms a bond with a neutral acid share an electron pair.
- Solid base – It is active in solid form. Examples are silicon dioxide and sodium hydroxide mounted on alumina.
Examples of bases are sodium hydroxide, calcium carbonate and potassium oxide.
A base is a substance that can neutralize the acid by reacting with hydrogen ions. Most bases are minerals that react with acids to form water and salts. Bases include the oxides, hydroxides and carbonates of metals.
The soluble bases are called alkalis. Sodium hydroxide is an alkali. Copper(ll) oxide is insoluble in water, so it is a base but not an alkali. Therefore, All alkalis are bases, but not all bases are alkalis. Bases have a slippery feel and taste bitter. Bases are defined as proton (H+) acceptors. Common examples of bases include metal oxides and metal hydroxides and ammonium hydroxide
Properties of Base
- Aqueous base solution dissociates into ions to conduct electricity.
- It has a pH value greater than 7.
- They form salts on reacting with acids.
- They help in promoting certain chemical reactions.
- They are bitter to taste if placed in alkali solutions.
- Strong or concentrated bases are caustic.
- It changes the indicator color from red litmus paper to blue litmus paper.
- It has the ability to accept protons from proton donors.
- It contains OH− ions.
- They vigorously react when in contact with acids.
- They are slippery to touch.
- They conduct electricity when dissolved in water.
Physical Properties of bases
PROPERTIES↓
- Color → Bases are colourless except the hydroxides of iron and copper.
- Taste → Bitter
- Touch → Slippery
- Solubility→ Some bases are soluble in water.
Chemical Properties of Bases
In the chemical properties of acids and bases, we now focus on bases.
- Bases change the colour of litmus from red to blue.
- They are bitter in taste.
- Bases lose their basicity when mixed with acids.
- Bases react with acids to form salt and water. This process is called Neutralisation Reaction(Read).
- They can conduct electricity.
- Bases feel slippery or soapy.
- Some bases are great conductors of electricity.
- Bases like sodium hydroxide, potassium hydroxide, etc are used as electrolytes.
- Alkalis are bases that produce hydroxyl ions (OH-) when mixed with water.
- Strong alkalis are highly corrosive in nature whereas other alkalis are mildly corrosive.
- The pH value of bases ranges from 8-14.
- Alkalis and ammonium salts produce ammonia.
- Hydrogen gas is evolved when metals react with a base.
- Bases are classified on the basis of strength, concentration and acidity.
- The different kinds of acids are strong base acid, weak base acid, concentrated base, dilute base, monoacidic base, diacidic base and triacidic base.
What are the uses of Bases
Uses of Bases
1. Calcium Hydroxide (Slaked lime) [Ca(OH)2]
- It is used to neutralize the acidity in soils.
- It is an ingredient in whitewash and mortar.
- It is a component of the Bordeaux mixture used for protecting agricultural crops from pests.
- It is used in the preparation of dry mixes for painting and decorating.
2. Magnesium Hydroxide (Milk of magnesia) [Mg(OH)2]
- It is used as an antacid or a laxative. It helps to correct excess acidity in the stomach.
3. Sodium Hydroxide (Caustic soda) (NaOH)
- It is used in the manufacture of paper, textiles, and detergents.
- In homes, it is occasionally used to unblock drains.
- It is used in the manufacture of soaps and detergents.
↓For more information search the link below↓
https://byjus.com/chemistry/propertries-of-acids-and-bases/
https://www.aplustopper.com/the-uses-of-bases/
#carryonlearning
