A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?

(A) Lemon juice

(B) Vinegar

(C) Common salt

(D) An antacid


Universal Indicator-Teachoo.jpg


  • Yellowish-orange color indicates that the soil is slightly acidic .
  • In order to change the color to greenish blue, we add a base so that the pH is increased .


Among the following options, 

  • Lemon juice and vinegar are acidic, 
  • common salt is neutral and
  •   antacid is basic.


So, the correct option is (d) an antacid

  1. Class 10
  2. Chapter 2 Class 10 - Acids, Bases and Salts (Term 1)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo