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
(C) Common salt
(D) An antacid
- 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