Question

Which of the following solutions is the most acidic?

• A. $\text{pH} = 6$
• B. $\text{pH} = 4$
• C. $\text{pH} = 9$
• D. $\text{pH} = 7$

Hint:

Solutions with $\text{pH}<7$ are acidic, $\text{pH}>7$ are basic, and $\text{pH} = 7$ is neutral. Acidity increases exponentially as $\text{pH}$ approaches 0.

Answer 1

The Correct Option is B

Acidity is inversely related to the $\text{pH}$ value.
A lower $\text{pH}$ corresponds to a higher concentration of hydrogen ions $[\text{H}^+]$ and thus greater acidity.
The options are compared: $4<6<7<9$.
The smallest $\text{pH}$ value listed is $\text{pH}=4$.
Therefore, the solution with $\text{pH}=4$ is the most acidic.