In daily life we meet many food substances. Substances like tamarind, grapes, curd and lemon are sour and are said to be acidic. Substances like sodium bicarbonate and soap are bitter and are said to be basic. Acids and bases are one of the important classifications of chemical compounds and are biologically, industrially and environmentally important. Among medicines, aspirin is acidic and antacids are basic. Dietary fats are acids and the chemical compounds in DNA are bases.
1. Acids – Meaning and Definition
- The term acid comes from the Latin word 'acidus', which means sour. Chemical compounds with a sour taste are generally called acids.
- All acids contain one or more replaceable hydrogen atoms in their molecules and release H+ ions when dissolved in water.
- Definition: Acids are chemical substances which release hydrogen ions when dissolved in water.
- Examples: Hydrochloric acid (HCl), Sulphuric acid (H2SO4) and Nitric acid (HNO3).