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
Answer:D
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
Explanation: pH paper gives greenish-blue colour in a weak alkaline medium so antacid [Mg(OH)2] which is an alkaline compound will show greenish-blue color on pH paper.