What is pH? Explore its Role In Science Laboratory And Beyond

What is pH

What is pH? Explore its Role In Science Laboratory And Beyond

Posted on the 18th of Aug 2023 by Westlab

In the bustling environment of a laboratory, whether it's a chemistry, biology, or environmental science lab, one of the most commonly measured and adjusted parameters is the pH. 

So, let’s understand what is pH, and how is it measured in laboratory procedures.

What Is pH Level And How Is It Essential For The Laboratory?

What is pH level? The term "pH" stands for "potential of hydrogen," and it is the number of hydrogen ions in a distilled or laboratory solution that describes the pH status. It shows the level of acidity or alkalinity of a solution. At its core, the pH scale ranges from 0 to 14. 

A pH less than 7 shows an acidic solution, a pH greater than 7 denotes a basic or alkaline solution, and a pH of 7 is neutral. 

This scale is logarithmic, meaning each unit change represents a decimal difference in hydrogen ion concentration. The more dense ions, the more acidic a solution will be. Likewise, the more distant the ions are in the solution, the more alkaline will the solution be. 

In the laboratory, pH can be measured using litmus paper, pH indicator solutions, or, more accurately, with a pH meter. The most accurate one is the pH meter, as it gives results in digital form with 100 percent accuracy and precision.

A laboratory lab cannot compromise the accuracy of tests, so these meters play a vital role in experiments. The pH level in a laboratory setting is fundamental for many more reasons. Ensuring the pH is controlled and maintained at desired levels can be crucial for experiment accuracy, reliability, and reproducibility. 

Here's why pH level is so important.

Chemical Reactions

The rate and direction of many chemical reactions are influenced by pH. Some reactions only proceed under acidic or basic conditions. By controlling pH, chemists can ensure that a reaction goes to completion or produces a desired product.

Stability of Compounds

Some compounds are stable only within specific pH ranges. If the pH deviates from this range, the combination might degrade or react with other substances in the solution. To get the perfect results, scientists must neutralize the pH level of the solution. 


The solubility of many compounds is pH-dependent. This is particularly important in processes like extraction, purification, or recrystallization, where solubility is critical. A minor change in pH level can change the solubility ability of any solution. 


Buffers, which resist changes in pH, are commonly used in labs. The effectiveness of a buffer is determined by its pKa value, which is directly related to pH. pKa is a number that defines the acidity of a particular molecule. Using a suitable buffer ensures that pH remains stable throughout an experiment.

Titration Accuracy

 Titrations are often used to determine the concentration of unknown solutions. Accurate readings and endpoints are dependent on correct pH measurements. In such experiments, pH levels can change results by minor differences in numbers or colors. 

Equipment Calibration

Instruments like pH meters or water testing kits need regular calibration to ensure accuracy. Regular checks and adjustments ensure that the pH measurements provided by these instruments are accurate.


Some chemicals can become reactive or hazardous under extreme pH conditions. Maintaining the correct pH can prevent dangerous reactions or by-products.

Given these factors, it's evident that maintaining and understanding pH levels in the lab is crucial - not just for scientific accuracy but also for the safety and effectiveness of many lab processes.

How is pH of Distilled Water Measured?

Measuring the pH of distilled water, or any other solution, usually involves using a pH meter, which contains an electrode sensitive to the hydrogen ion concentration in the solution. 

Here's a step-by-step guide to measuring the pH level of distilled water.

Step 1 - Preparation

To accurately measure the pH of distilled water, begin with equipment preparation. First, it's essential to have a well-calibrated pH meter at hand. Calibration is generally accomplished with standard buffer solutions with known pH values, often pH 4, 7, and 10. 

Alongside the pH meter, the cleanliness of the electrode is paramount. If the electrode has been stored dry, it's recommended to immerse it in an electrode storage solution for a minimum of an hour to clean it.

Step 2 - Rinsing of The Meter And Electrode

Before the measurement, the electrode requires a thorough rinse with distilled water. This ensures that any residues, either from the storage solution or from previous measurements, are eliminated. 

When rinsing, it's vital to handle the electrode with care. Gently shaking off the excess water or dabbing with a laboratory tissue is advised, but direct rubbing can damage the sensitive electrode.

Step 3 - Pour Distilled Water or Solution

With the preparations complete, proceed to the actual pH measurement. Start by pouring a fresh sample of distilled water or solution into a clean container, such as a beaker. Submerge the pH electrode into this sample, ensuring it doesn’t contact the container's base or sides. 

Step 4 - Record The Reading

As the equipment starts to read the sample's pH, the reading might take several minutes to stabilize. Once stable, record the pH value as displayed on the meter. Ideally, distilled water, when measured at 25°C (77°F), should reflect a pH close to 7. 

If we measure the pH of tap water, the reading would be 6.5 to 8.5. The fluctuation may be because of changes in temperature, carbon dioxide ions, and heat. These steps are the same for any simple or complex solutions. 

We discussed what is pH and how it works in detail. Learning pH levels and numbers in a lab experiment increases the chance of an accurate result. It can help scientists to deduce solutions for many problems. 

pH meters play a vital role in determining pH levels in the solution. Westlab Australia has a wide range of pH meters in stock. Just visit our website and get it delivered to your doorstep. 


2023-08-18 13:30:00
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