Acid
Definition:
An acid is a chemical substance that typically has a sour taste, the ability to react with bases, and the ability to turn certain indicators red. It is characterized by having a low pH value (less than 7) and by donating protons or accepting electrons.
Properties of Acids:
- Sour taste: Acids generally have a sour or tart taste, which is highly evident in substances like lemon juice or vinegar.
- Reactivity with bases: Acids readily react with bases to form salts and water through a chemical process called neutralization. This reaction is often accompanied by the production of heat.
- Indicator color change: Acidic solutions can cause specific indicators, such as litmus paper, to turn red.
- Low pH: Acids have a pH value lower than 7 on the pH scale, indicating their high concentration of hydrogen ions (H+).
- Proton donors: Acids donate protons (H+) to other substances during chemical reactions.
- Electron acceptors: Acids can also accept electrons (e-) from other substances, exhibiting an electron-pair acceptor behavior in certain reactions.
Examples:
Common examples of acids include:
- Hydrochloric acid (HCl): A strong acid found in the gastric acid of the stomach.
- Sulfuric acid (H2SO4): A highly corrosive acid commonly used in industrial processes.
- Acetic acid (CH3COOH): The acid responsible for the sour taste in vinegar.
- Citric acid (C6H8O7): A natural acid present in citrus fruits like lemons and oranges.