Exploring Substances: Acidic, Basic, and Neutral - What Happens When Acidic Substances Mix with Basic Substances?
Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
A reaction between an acid and a base is called a Neutralization reaction. In this process, both the acidic nature of the acid and the basic nature of the base are destroyed.
The products formed in a neutralization reaction are Salt and Water. A salt can be acidic, basic, or neutral in nature depending on the strength of the reacting acid and base.
Neutralization is an exothermic process, meaning heat is always produced or evolved. This causes the temperature of the reaction mixture to rise.
The indicator Phenolphthalein is commonly used to observe neutralization. It turns deep pink in a basic solution and remains colorless in acidic or neutral solutions.
Neutralization in Daily Life: Indigestion is treated with antacids like Milk of Magnesia (); Ant stings (formic acid) are neutralized with moist baking soda () or calamine (); Soil treatment involves adding quick lime () or slaked lime () to acidic soil.
Factory wastes are often acidic and must be neutralized with basic substances before being discharged into water bodies to protect aquatic life.
📐Formulae
💡Examples
Problem 1:
A student takes of dilute and adds a drop of phenolphthalein. Then, they add drop by drop while shaking. What changes occur when the solution just turns neutral?
Solution:
The pink color just begins to appear and then stays upon reaching the neutralization point.
Explanation:
Initially, the solution is acidic, so phenolphthalein is colorless. As (a base) is added, it reacts with to form and . At the exact point where all acid is neutralized, the addition of one extra drop of base makes the solution slightly basic, turning the phenolphthalein pink.
Problem 2:
Explain the chemical process behind treating an ant sting with baking soda.
Solution:
Explanation:
When an ant bites, it injects an acidic liquid, formic acid (), into the skin. To neutralize this, a mild base like baking soda () or calamine solution (zinc carbonate) is applied. The base reacts with the acid to form salt and water, neutralizing the burning sensation.
Problem 3:
If the soil is too basic, how is it treated for better plant growth?
Solution:
Organic matter (compost) is added to the soil.
Explanation:
Organic matter releases acids as it decays. These acids neutralize the basic nature of the soil, making it suitable for plants that require a neutral or slightly different balance.