3 ways to measure the pH of water

Table of contents:

3 ways to measure the pH of water
3 ways to measure the pH of water
Anonim

It is important to measure the pH levels (levels of acidity or alkalinity) of the water. Water is consumed by plants and animals on which we depend and we consume it directly every day. The pH level of the water can provide information on possible contamination. Therefore, measuring the pH level of water can be an important public health precaution.

Steps

Method 1 of 3: Use a pH meter

Measure the pH of Water Step 1
Measure the pH of Water Step 1

Step 1. Calibrate the probe and meter to the manufacturer's specifications

You may need to calibrate the meter by testing it in a substance for which you know the pH level. This is how you can adjust the meter. If you are going to test the water outside of a laboratory, it is best to perform this calibration hours before taking the meter to the field.

Rinse the probe with clean water before use. Dry it with a clean cloth

Measure the pH of Water Step 2
Measure the pH of Water Step 2

Step 2. Collect a water sample in a clean container

  • The water sample should be deep enough to cover the tip of the electrode.
  • Let the sample sit for a moment so the temperature can stabilize.
  • Measure the temperature of the sample using a thermometer.
Measure the pH of Water Step 3
Measure the pH of Water Step 3

Step 3. Adjust the meter to match the temperature of the sample

The sensitivity of the probe is affected by the temperature of the water, which is why the meter reading cannot be accurate if you do not enter the temperature information.

Measure the pH of Water Step 4
Measure the pH of Water Step 4

Step 4. Place the probe in the sample

Wait for the meter to balance. The meter reaches a balance point when it stabilizes.

Measure the pH of Water Step 5
Measure the pH of Water Step 5

Step 5. Read the pH measurements of the sample

The pH meter should provide a reading on a scale of 0-14. If the water is pure it should read a number close to 7. Record your findings.

Method 2 of 3: Use litmus papers

Measure the pH of Water Step 6
Measure the pH of Water Step 6

Step 1. Know the difference between pH paper and litmus paper

To get an accurate reading on a solution, you can use pH paper. Make no mistake, this is not your ordinary litmus paper. Both can be used to test for acids and bases, but they are different in very important ways.

  • The pH strips contain a series of indicator bars that change color after exposure to the solution. The strength of the acids and bases in each bar are different. After they change, you can see which example (of the ones in the kit) the color patterns of the bars match.
  • Litmus paper is strips of paper that contain an acid or a base (alkaline). The most common are red (which contain an acid that reacts with bases) and blue (which contain a base that reacts with acids). Red strips turn blue if the substance is alkaline and blue strips turn red if they come in contact with an acidic substance. Litmus paper can be used as a quick and easy test, but the cheapest ones do not always provide accurate readings on the strength of the solution.
Measure the pH of Water Step 7
Measure the pH of Water Step 7

Step 2. Collect a water sample in a clean container

The water sample should be deep enough to cover the strip.

Measure the pH of Water Step 8
Measure the pH of Water Step 8

Step 3. Dip the test strip into your sample

With a few seconds you have. The different indicator bars on the paper will start to change color in a couple of minutes.

Measure the pH of Water Step 9
Measure the pH of Water Step 9

Step 4. Compare the test strip to the color chart that came with the paper

The colors in the table should match the colors on your test strip. The table should correlate the color patterns to the pH levels.

Method 3 of 3: Understand what pH is

Measure the pH of Water Step 10
Measure the pH of Water Step 10

Step 1. Learn how acids and bases are defined

Acid and alkalinity (the term is used to describe bases) are both defined by the hydrogen ions they lose or accept. An acid is a substance that loses (or, as some say, donates) hydrogen ions. A base is a substance that accepts additional hydrogen ions.

Measure the pH of Water Step 11
Measure the pH of Water Step 11

Step 2. Understand the pH scale

The pH number is used to rate the level of acidity or alkalinity of soluble substances in water. Water normally contains an equal amount of hydroxide ions (OH-) and hydronium ions (H30 +). When an acidic or alkaline substance is added to water, it changes the ratio of hydroxide ions and hydronium ions.

  • It is commonly said to be on a scale of 0 to 14 (although substances can usually fall beyond that range). Neutral substances enter around 7, acidic substances below 7 and alkaline substances above 7.
  • The pH scale is a logarithmic scale, which means that the difference of a single integer represents a huge difference in acidity or alkalinity. For example, a substance that has a pH of 2 is actually 10 times more acidic than one with a pH of 3 and 100 times more acidic than a substance with a pH of 4. The scale works the same for alkaline substances, with an integer representing a ten-fold difference in alkalinity.
Measure the pH of Water Step 12
Measure the pH of Water Step 12

Step 3. Find out why tests are needed to measure the pH of the water

Pure water should have a pH of 7, although tap water has a pH of between 6 and 5.5. Acidic water (water with a lower pH) easily dissolves toxic chemicals. These can contaminate the water and make it unsafe for human consumption.

Popular by topic