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?
  1. Lemon juice
  2. Vinegar
  3. Common salt
  4. An antacid

AcademicChemistryNCERTClass 10

Correct Answer:    (d) An antacid

Explanation: As pH paper turns greenish blue for weakly basic compound and antacids contain weak base like Mg(OH)2. So, an antacid would change the colour of this pH paper to greenish-blue. 

raja
Updated on 10-Oct-2022 12:46:49

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