Tools

Soil Analysis-Determination of pH of Soil

Procedure

Determination of Soil pH:

  1. The pH meter was calibrated using pH 7 buffer solution.
  2. Then the meter was adjusted with known pH of buffer solutions 4.0 and 9.2.
  3. 20 g of soil was weighed and transferred into 100 mL beaker.
  4. 40 mL distilled water was added and stirred well with a glass rod.
  5. This was allowed to stand for half an hour with intermittent stirring.
  6. To the soil water suspension in the beaker, the electrode was immersed and pH value was determined from the automatic display of the pH meter.

Points to Remember while Performing the Experiment in a Real Laboratory:

  • Always wear lab coat and gloves when you are in the lab.
  • When you enter the lab, switch on the exhaust fan and make sure that all the chemicals and reagents required for the experiment are available. If not, prepare the reagents using the components for reagent preparation.
  • Properly adjust the flame of the Bunsen burner. The proper flame is a small blue cone; it is not a large plume, nor is it orange.
  • Make sure to clean all your working apparatus with chromic acid and distilled water and ensure that all the apparatus are free from water droplets while performing the experiment.
  • Make sure to calibrate the electronic weigh balance before taking the measurements.
  • Ensure that the desiccator has sufficient amount of desiccant; Silica gel.
  • Use chromic acid to clean the crucible, then heat it and make sure to cool it before placing in the desiccator. Handle the crucible with cleaned tongs or tissue paper. Never touch it with your hand.
  • Switch on the oven and adjust the temperature to 130°C. Use a cotton glove while working with a hot air oven.
  • Make sure to clean the Kipp's apparatus tube with water and ensure that it has sufficient solid material; iron sulfide and acid (H₂SO₄) for producing H₂S gas.
  • Clean all glassware with soap and distilled water.
  • Once the experiment is completed, recap the reagent bottles. Switch off the light, exhaust fan, hot air oven, and gas cylinder before leaving the lab.
  • Discard the used gloves in a waste bin.