Acids are used in industries to manufacture fertilizers, paints, dyes and man-made fibers, while bases are used in the production of fabrics, cleaning agents and paper. In nutrition, diluted acids are used to dress salads and vegetables, giving food a distinctive taste. For example, vinegar contains 3 percent acetic acid. Citrus fruits have citric acid. Aspirin contains acetylsalicylic acid, and wine has tartaric acid.
Acids are present in the stomachs of humans to help with the digestion of food. The absence of acids in the proper levels may cause indigestion and bloating. However, too much acid is dangerous, as it may corrode the stomach lining. However, antacids manufactured from bases can be used to neutralize the excess acid.
Bases have a bitter taste and are not recommended for human consumption. However, some substances containing nitrogen-rich bases such as caffeine and nicotine are frequently used by humans. In addition, tonic water draws its bitter taste from the alkaloid quinine. Bases are used in cleaning detergents for their characteristic slippery nature. Sodium hydroxide in lye effectively dissolves protein and grease and is commonly used in cleaning products and lotions.
In the ocean, a balanced water pH level is essential for supporting the lives of animals and plants.