pH in Acids, Bases and Salts – Class 10 Science Experiment

Chapter Name: Acids, Bases and Salts

Activity Name: pH in Acids, Bases and Salts

Activity Description:

In this experiment, we will determine the pH of soil using a simple filtration and pH testing method. The pH level of soil is crucial for the growth of plants, and we will use universal indicator paper to measure the pH of the soil filtrate.

Required Items:

  1. Soil sample (approximately 2g)
  2. Water (5ml)
  3. Test tubes
  4. Filter paper
  5. Universal indicator paper
  6. Quicklime (calcium hydroxide) or calcium carbonate (for discussion purposes)

Step by Step Procedure:

  1. Take about 2g of soil and place it in a test tube.
  2. Add 5ml of water to the test tube containing the soil.
  3. Shake the contents of the test tube thoroughly to ensure proper mixing of soil and water.
  4. Set up a filtration system using filter paper to filter the contents of the test tube. Collect the filtrate in another clean test tube.
  5. Take a piece of universal indicator paper and dip it into the filtrate for a few seconds.
  6. Remove the indicator paper and observe the color change. Compare the color to the pH color chart to determine the pH level of the soil.

Experiment Observations:

  • The pH level of the soil will be determined based on the color change of the universal indicator paper.
  • The color observed on the indicator paper will correspond to a specific pH value.


  1. Make sure the test tubes and equipment used are clean to avoid contamination.
  2. Handle the universal indicator paper carefully to avoid any contact with skin or eyes.
  3. Follow standard laboratory safety practices while conducting the experiment.

Lesson Learnt from Experiment:

  1. The ideal soil pH for the growth of plants in your region can be inferred from the pH value obtained from the soil sample. Different plants thrive in different pH ranges, so understanding the pH of the soil can help determine which plants are best suited for the area.
  2. If the pH of the soil is too acidic (low pH value), a farmer may choose to treat the soil with quicklime (calcium hydroxide) or calcium carbonate to raise the pH level and make the soil more alkaline. This process is known as liming and is done to reduce soil acidity and improve plant growth.

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