pH of Acid and Base
pH value of a solution can be defined according to its ability of dissociation in H+ and the relative concentration of hydrogen ions in pure water. According to this, the solutions are classified as acids, bases and neutral. If the concentration of hydrogen in pure water is greater than 1 × 10-7 M, the solution acidic, if it is less than 1 × 10-7 M, the solution is termed as basic or alkaline. If the concentration of hydrogen in pure water is exactly 1 × 10-7 M, the solution will be neutral.
pH of Acids
Acids are molecules that can either donate a proton or can form a covalent bond with an electron pair. They are generally sour in taste and are corrosive in nature. It can turn blue litmus to red. Hydrochloric acid, sulfuric acid, acetic acid, boric acid are few examples of acids. Acids can either be strong or a weak acid. Strong acids dissociates to generate H+ more rapidly than weak acids. The strength of acids can be defined by its pH value. The pH value range of 0-6.9 determines the solution to be acidic. Lower the pH value, stronger is the acid. The acid having ph range of 0-4 are termed under strong acids, for example Hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid are strong acids. If the pH value of acids falls under pH range of 4-6.9, the acid can be termed as moderately weak or weak acids, acetic acid, boric acid are few examples for the same.
Few examples of acids along with their pH value are described below:
pH Value |
Acid Strength |
Example |
---|---|---|
0 |
Very strong |
Battery Acid |
1 |
strong |
Hydrochloric Acid |
2 |
moderately strong |
Lemon juice, Vinegar |
3 |
moderately strong |
Orange juice, Soda |
4 |
moderately weak |
Acid rain, Tomato |
5 |
weak |
Banana, Coffee |
6 |
very weak |
Milk |
pH of Bases
Bases on the other hand, are the molecules that can accept a proton and consists of OH– ions. They are generally bitter in taste. They are also termed as alkaline. It can turn red litmus to blue. Lubricating grease, Baking soda or baking powder, Soaps, Toothpaste are few examples of bases. Bases are also classified as strong and weak bases. Strong bases dissociates to generate OH– more rapidly than weak bases, strong bases dissociates into H+ in very less amount. The strength of bases can be defined by its pH value. The pH value range of 7.1-14 determines the solution to be basic. Higher the pH value, stronger is the base. The strongest base have a pH value of 14. The bases having ph range of 7.1 – 11 are termed under weak bases, for example: Ammonia (NH3), Calcium hydroxide (Ca(OH)2) and Magnesium hydroxide (Mg(OH)2) . The bases having pH range of 11-14 are termed as strong bases, for example: Sodium hydroxide (NaOH) and Potassium hydroxide (KOH).
Few examples of bases along with their pH value are described below:
pH Value |
Basic Strength |
Example |
---|---|---|
8 |
Very weak |
Sea water |
9 |
Weak |
Baking soda |
10 |
Moderately weak |
Antacid tablets |
11 |
Moderately strong |
Soap |
12 |
strong |
Ammonia |
13 |
strong |
Bleach |
14 |
very strong |
Drain cleaner |
If the pH value of a solution is 7, the solution is termed as neutral i.e. neither basic nor acidic.
pH of Acid and Base
pH stands for Potential of Hydrogen, which simply means the power of hydrogen in a compound. pH value helps determine the nature of the solution. It helps to define the acidity and basicity of a solution. pH value should be balanced for the proper well-being of the environment and living organisms.
This article will cover information about the pH of acid and base, the pH scale, the calculation of pH value and the importance of pH.
Table of Content
- What is pH in Chemistry?
- pH of Acid and Base
- pH scale
- Why does a Water Source Change pH?
- How to calculate pH ?
- Importance of pH