A solution has a pH of 3. How does it compare to a solution with a pH of 5?
AIt is 2 times more acidic
BIt is 20 times more acidic
CIt is 100 times more acidic
DIt is less acidic
Each step on the pH scale represents a tenfold change. From pH 5 to pH 4 is 10 times more acidic, and from pH 4 to pH 3 is another 10 times. So pH 3 is 10 x 10 = 100 times more acidic than pH 5.
Question 2 True / False
A solution with a pH of 7 is considered basic.
TTrue
FFalse
Answer: False
A pH of 7 is neutral — neither acidic nor basic. This is the pH of pure water. Solutions with pH below 7 are acidic, and solutions with pH above 7 are basic (alkaline).
Question 3 Short Answer
What is the approximate pH of stomach acid, and is it acidic, neutral, or basic?
Think about your answer, then reveal below.
Model answer: Stomach acid has a pH of about 1-2, and it is strongly acidic.
The hydrochloric acid in your stomach has a very low pH (about 1-2), making it one of the most acidic substances in your body. This strong acidity is necessary to break down food and kill harmful bacteria. Your stomach lining has special protective mechanisms to prevent the acid from damaging it.