In an acidic solution, [tex]pH[/tex] is \_\_\_\_\_\_ and [tex]\left[ H _3 O ^{+}\right][/tex] is \_\_\_\_\_\_

A) [tex]\ \textgreater \ 7,\ \textless \ 1 \times 10^{-7}[/tex] M
B) [tex]=7,1 \times 10^{-7}[/tex] M
C) [tex]\ \textless \ 7,\ \textless \ 1 \times 10^{-7}[/tex] M
D) [tex]\ \textless \ 7,\ \textgreater \ 1 \times 10^{-7}[/tex] M



Answer :

To determine the characteristics of an acidic solution, let's first understand the two main factors involved: pH and the concentration of hydrogen ions [tex]\([H_3O^+]\)[/tex].

1. pH of an acidic solution:
- pH is a scale used to specify the acidity or basicity of an aqueous solution.
- The pH scale ranges from 0 to 14.
- A pH value less than 7 indicates an acidic solution, while a pH greater than 7 indicates a basic (alkaline) solution. A pH of exactly 7 is neutral (pure water at 25°C).

2. Concentration of Hydrogen ions [tex]\([H_3O^+]\)[/tex]:
- The concentration of hydrogen ions [tex]\([H_3O^+]\)[/tex] directly determines the pH of a solution.
- The relationship between pH and [tex]\([H_3O^+]\)[/tex] can be expressed using the formula: [tex]\( \text{pH} = -\log[H_3O^+] \)[/tex].
- For a neutral solution (pH = 7), [tex]\([H_3O^+]\)[/tex] is [tex]\( 1 \times 10^{-7} \)[/tex] M.
- In an acidic solution, since the pH is less than 7, the concentration of [tex]\([H_3O^+]\)[/tex] must be greater than [tex]\( 1 \times 10^{-7} \)[/tex] M.

Given these explanations:

- An acidic solution has a pH less than 7.
- The concentration [tex]\([H_3O^+]\)[/tex] in an acidic solution is greater than [tex]\( 1 \times 10^{-7} \)[/tex] M.

Now, let’s examine the options:

A) [tex]\(>7, <1 \times 10^{-7} \text{ M}\)[/tex]
B) [tex]\(=7, 1 \times 10^{-7} \text{ M}\)[/tex]
C) [tex]\(<7, <1 \times 10^{-7} \text{ M}\)[/tex]
D) [tex]\(<7, >1 \times 10^{-7} \text{ M}\)[/tex]

Based on the characteristics of an acidic solution:

- The pH is less than 7.
- The concentration [tex]\([H_3O^+]\)[/tex] is greater than [tex]\( 1 \times 10^{-7} \)[/tex] M.

The correct answer is:
D) [tex]\(<7, >1 \times 10^{-7} \text{ M}\)[/tex]