Solution:The correct order of pH for the given substances isLemon juice < Coffee < Blood < Milk of magnesia
The pH range of Milk of Magnesia is 10-10.5. Milk of Magnesia is another name of Magnesium Hydroxide. It is used as an Antacid to neutralise excess acid present in the digestive system.
Normal pH range of human blood is 7.35 to 7.45. This means that blood is naturally slightly alkaline or basic. With an average pH of 4.85 to 5.10, most coffees are considered rather acidic.
Lemon juice has a pH between 2 and 3, which means it's 10,000-100,000 times more acidic than water (1, 2, 3).