PH Testing Filter Paper

Chemistry cannot do without solutions, which can be acids or bases. The “ruler” for testing the pH of a solution is the “extensive pH paper”, also known as the litmus paper. This is a kind of ready-made test filter paper. When using it, tear off a strip and put it on the surface dish. Dip a drop of solution into the glass container with a dry glass rod. Qualitative Filter Paper Disc Grade: BIO-1, Qualitative Laboratory Filtration Filter Paper Grade: BIO-2, Quantitative Laboratory Filter Paper Grade: BIO-42.

pH testing filter paper is a special type of filter paper that is impregnated with specific pH indicators. These indicators change color in response to changes in the pH level of a solution, allowing for a quick and convenient way to determine the pH of a sample. Here’s how pH testing filter paper works and how to use it:

Method editing

1. Test the acidity and alkalinity of the solution: take a small piece of test paper on the surface dish or glass sheet, dip a clean and dry glass stick into the middle of the test paper, observe the color after stable change, and compare with the standard color card to judge the nature of the solution.

2. Test the acidity and alkalinity of the gas: first wet the test filter paper with distilled water, stick it to one end of the glass rod, and then send it to the mouth of the container where the gas to be tested is stored. Observe the color change and judge the nature of the gas. (the paper cannot touch the wall)

3. Chemical information editing
PH paper application is very extensive, pH of the reaction principle is based on the pH indicator method, the general analysis of the pH value of the test paper containing methyl red [pH4.2 (red) to 6.2 (yellow)], bromocresol green [pH3.6 (yellow) to 5.4 (green)] bromine thyme phenol blue (yellow) [6.0 ~ 7.6 (blue)], this mixed acid-base indicator with a moderate amount of alcohol can reflect the variation range of pH 4.5 ~ 9.0.

Specification: Width: 39/93/125cm .

How pH Testing Filter Paper Works:

  1. pH Indicators: pH indicators are substances that change color in response to changes in the pH of a solution. They are usually weak acids or bases that undergo a reversible color change.
  2. Impregnation: pH testing filter paper is impregnated or coated with a pH indicator. The type of indicator used determines the range of pH values the paper can measure.
  3. Color Change: When the pH testing filter paper comes into contact with a solution, the pH indicator reacts with the hydrogen ions (H+) or hydroxide ions (OH-) present, causing a color change.
    • For example, litmus paper turns red in acidic solutions and blue in basic solutions.

How to Use pH Testing Filter Paper:

  1. Prepare the Sample:
    • Obtain a small sample of the solution you want to test. If it’s a liquid, ensure it’s in a container that allows easy access for the filter paper.
  2. Retrieve a Strip of pH Testing Filter Paper:
    • Use clean and dry hands or tweezers to handle the pH testing strip. Avoid touching the indicator area with your fingers.
  3. Dip the Filter Paper into the Solution:
    • Gently dip the indicator area of the pH testing strip into the solution. Ensure it is fully submerged for a few seconds.
  4. Observe the Color Change:
    • Remove the pH testing strip from the solution and observe any color change on the indicator area.
    • Compare the color of the indicator area to a pH color chart provided by the manufacturer. This chart will indicate the approximate pH of the solution.
  5. Dispose or Rinse the Strip (If Necessary):
    • Depending on the type of pH testing strip used, you may need to dispose of it after a single use or rinse it for reuse.


  • Always handle pH testing strips with clean and dry hands or tweezers to avoid contamination.
  • Ensure the indicator area is fully immersed in the solution to get an accurate reading.
  • Avoid using pH testing strips that have expired, as they may provide inaccurate results.
  • Follow any specific instructions provided by the manufacturer for the particular pH testing strip you are using.

PH testing filter paper provides a quick and convenient method for determining the pH of a solution, making it a valuable tool in various laboratory and field applications.