pH measurement

Free Preview

pH is used to measure the acidity and alkalinity of a liquid. pH was first defined as the negative logarithm of the hydrogen ion concentration, to simplify the handling of the very small concentrations encountered most commonly in nature.

It is essential to know whether the solution is acidic and basic because of a situation wherein it can hinder elements’ growth from being absorbed by the root structure. pH scale starts from 0 to 14, the solution is said to be acidic if the pH value lies between 0 to 7 and basic when the pH value is between 7 to 14.

Following are the methods to measure pH:

  1. Indicators paper or pH paper: This method is a cheap way of measuring but not an accurate measurement. Using an organic dye, this coated paper changes color according to the solution whether it is acid or base. This method is easy to test. Litmus paper measurement is only for noncritical measurements. This can be done by dipping a strip (pH paper) into the sample for a few seconds and wait for the indicator bars on the paper to change color. Compare the end of the test strip with the color chart that came with the paper to establish the pH level of the liquid.
  2. pH meters: This measurement is most accurate and is widely used. These are relatively less expensive, easy to use and compact (pocket-sized meters). These are more often used in the food industry.

Recently, multiparameter meters are being commonly used not only for pH measurement but also for temperature, pressure, salinity, dissolved oxygen, etc. The measurements using these meters are precise and accurate.

Back to: Instrumentation and Control

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.