Acids and Bases:
Acids are substances that produce hydrogen ions (H+) when dissolved in water, resulting in a solution with a pH less than 7. Bases, on the other hand, produce hydroxide ions (OH-) in water and have a pH greater than 7.
Properties of Acids and Bases:
Acids:
- Sour taste
- React with metals to produce hydrogen gas
- Turn blue litmus paper red
- Have a pH less than 7
Bases:
- Bitter taste
- Slippery to the touch
- Turn red litmus paper blue
- Have a pH greater than 7
Uses of Acids and Bases:
Acids:
- In the production of fertilizers and dyes
- As a cleaning agent for removing rust and mineral deposits
- In the production of batteries
- In food preservation
Bases:
- As a cleaning agent for removing grease and oil
- In the production of soaps and detergents
- In water treatment to remove impurities
- As a pH adjuster in cosmetics and personal care products
Neutralization reactions:
Acids and bases react with each other to form a neutral solution, with a pH of 7. This reaction is called neutralization. When an acid and base react, they form a salt and water. For example, the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) produces sodium chloride (NaCl) and water:
HCl + NaOH → NaCl + H2O
Preparation of Salts:
Salts can be prepared by neutralizing an acid with a base, or by reacting an acid with a metal or a base. The salt formed will depend on the acid and base used in the reaction. For example, the reaction between hydrochloric acid (HCl) and calcium hydroxide (Ca(OH)2) produces calcium chloride (CaCl2) and water:
HCl + Ca(OH)2 → CaCl2 + H2O