Alkali

An alkali is a water-soluble salt of an alkali metal (sodium, potassium, etc.) or alkaline earth metal (calcium, magnesium, etc.). These substances have a pH greater than 7 (basic) and neutralize acids. Alkalis typically taste bitter, feel slippery, and can cause severe burns. They react strongly with acids, forming salts and water, and are widely used in various industrial and domestic applications. The term originates from the Arabic word 'al-qali', referring to the ashes from which alkaline substances were originally extracted. They are strong bases.

Alkali meaning with examples

• Sodium hydroxide (lye), a common alkali, is used to make soap. Its basic properties enable the saponification of fats. Caustic soda, another name for it, is corrosive and capable of causing severe skin burns. The powerful base readily absorbs moisture from the air (deliquescent). This is just one of the numerous everyday utilizations of alkalis in household cleaning products.
• In a chemistry experiment, a student added hydrochloric acid to a solution of potassium hydroxide (KOH), an alkali. A vigorous reaction, accompanied by heat evolution, occurred as the acid neutralized the base. Salt and water, being neutral, were the end products. This demonstrated the characteristic reaction of alkalis with acids, a fundamental concept in acid-base chemistry.
• Certain types of soil can be alkaline (high pH) due to the presence of alkalis. This impacts plant growth, as many plants thrive in slightly acidic or neutral conditions. The gardener added sulfur to the soil to lower the pH. This process makes the soil more suitable for acid-loving plants to absorb nutrients effectively, promoting healthier vegetation.
• Baking soda (sodium bicarbonate), a mild alkali, is used in baking to produce carbon dioxide, causing the dough to rise. When baking soda is combined with an acidic ingredient, such as lemon juice or buttermilk, a chemical reaction occurs. It gives products a fluffy texture. This highlights the practical use of alkalis in food science and culinary arts.