Question

0.39. 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-bule ?
a. Lemon juice b. Vinegar
c. Common salt d. An antacid.​

Answer 1

the soil solution turns pH paper yellow it means that the pH of the soil is between 2-4 .so to turn the pH paper to greenish blue we will add a base to the soil solution that is we will add an antacid to the soil (since antacid is basic in nature )