Alkali

Definition

Alkali: A chemical substance that neutralizes acids to form neutral salts. It is a type of base and is the opposite of an acid. Examples include ammonia and caustic soda.

Purpose

The primary purpose of alkalis is to neutralize acidic substances, resulting in the formation of neutral salts and water. This neutralization process is crucial in various industrial, agricultural, and environmental applications. Alkalis are used to maintain pH balance, facilitate chemical reactions, and in the manufacturing of numerous products.

Examples of Use

1. Industrial Cleaning: Alkalis like caustic soda (sodium hydroxide) are used in industrial cleaning agents to break down grease and organic materials.
2. Water Treatment: Alkalis help in adjusting the pH of water, making it less corrosive and more suitable for consumption and industrial use.
3. Agriculture: Lime (calcium hydroxide) is applied to acidic soils to increase pH levels, improving soil health and crop yields.
4. Soap Making: Sodium hydroxide is a key ingredient in the saponification process, where fats and oils are converted into soap.
5. Food Processing: Alkalis such as baking soda (sodium bicarbonate) are used in food preparation and preservation, for tasks like leavening baked goods and regulating acidity.

Related Terms

• Acid: A substance that donates hydrogen ions (H+) and can neutralize alkalis to form salts.
• Base: A substance that accepts hydrogen ions (H+) and can neutralize acids. Alkalis are a subset of bases that are soluble in water.
• Neutralization: A chemical reaction between an acid and a base, resulting in the formation of a salt and water.
• pH: A scale used to measure the acidity or alkalinity of a solution, where 7 is neutral, below 7 is acidic, and above 7 is alkaline.
• Buffer: A solution that resists changes in pH when small amounts of acid or alkali are added.

Notes

• Alkalis can be corrosive and must be handled with care, using appropriate safety measures such as gloves and eye protection.
• The strength of an alkali is determined by its ability to dissociate in water, with strong alkalis like sodium hydroxide fully dissociating into ions.
• In environmental contexts, alkalis are used to neutralize acidic pollutants, such as in acid rain treatment and industrial effluent management.