Question:
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
Solution:
(d). The colour of the pH paper signifies that the solution is somewhat acidic. In order to change it to greenish-blue, we need an antacid.