pH Scale-Definition, Importance, and Factors

pH is the measure of acidity or alkalinity of a solution. The human body has a natural balance between acidity and alkalinity. The pH of water is a measure of how acidic or basic it is. pH is a measure of the relative amount of free hydrogen and hydroxyl ions in the water.

pH Scale

The pH scale is one way of measuring how acidic or basic a solution is. It has a range from 0 to 14 but can go beyond that if the solution is particularly acidic or basic. The pH value is determined by the concentration of hydrogen ions in a solution. The pH to H+ formula that represents this relation is:

pH=−log ([H+])

The solution is acidic if its pH is less than 7. If the pH is higher, the solution is basic (also referred to as alkaline). Solutions with a pH that is equal to 7 are neutral.

There are different ways that you can test the pH of a solution. One way is by using pH indicators. The most popular pH indicator is litmus paper. Litmus paper changes color depending on the acidity or alkalinity of the solution it was dipped in.

Importance of pH

• The pH of the human body is important for a variety of reasons, but it is especially crucial for our digestive system. All of the physiological reactions in the body take place within a pH range of 7 to 7.8.
• pH is especially important in our digestive system – for example, hydrochloric acid is secreted into the stomach as food enters it. This helps to maintain a pH of 1-3 in the stomach.
• The pH of your stomach is important for more than just keeping things moving along. It’s also responsible for the activation of the enzyme pepsin. Pepsin helps with the digestion of protein in food, which is an essential piece of keeping you healthy and satisfied after a meal.
• Our tooth starts decaying when the pH of our mouth falls below 5.5.
• Tooth powder and toothpaste which are used for cleaning teeth are basic.

Factors affecting the pH of the water

The following factors affect the pH of water;

1. CO2 Concentration in Water

A factor that affects pH is the concentration of carbon dioxide dissolved in water. Carbon dioxide causes an increase in the concentration of hydrogen ions which causes the water’s pH to decrease. That means when carbon dioxide is high, the water becomes acidic. While during the day, when many plants photosynthesize by releasing oxygen, the pH of the water will rise.

2. Temperature

The temperature of the water can affect how much carbon dioxide is dissolved in it. When water is heated up by the sun, the surface temperature will increase. When the surface temperature of the water rises, the amount of carbon dioxide that can be dissolved in it will decrease, which will make the pH of the water rise and make the water more alkaline.

Meanwhile, when the temperature decreases, the surface temperature of the water will also decrease and more carbon dioxide will be able to dissolve in it. Therefore, when temperatures are cold, the pH of the water will drop.

3. Carbonate and Bicarbonate Concentrations

The factors that affect the pH are carbonate and Bicarbonate ion, which are basic. The water’s pH will change if there is a high concentration of carbonate and bicarbonate in the water. The water will turn into a base from where it was originally neutral.

It can become neutral if it is initially acidic. Water flowing out of the mouth of the cave can be changed into a base by passing carbonate rocks with calcium.

4. Organic Material Decomposition Process

Decomposition is the process of deterioration that takes place in living organisms and organic matter. This is because organic matter and living organisms contain the element carbon (C). So when decomposition occurs, carbon is emitted into the water.

Nevertheless, organic substances are fragile and easily oxidized, meaning that what goes into the water is carbon dioxide and water. Therefore, it is certain that the pH level will change when there is carbon dioxide entering the water.

Water that was originally neutral can become acidic because the dissolved inorganic carbon content can increase hydrogen ions, thereby decreasing the pH. Therefore, it is better to keep water away from organic materials that can change the initial pH when working in a laboratory or industrial production process.