If the pH value is 4.5 for a solution then what is the value of `H^(+)` concentration?

Options

A. `3.162 xx 10^(-5)` mol/L
B. `31.62 xx 10^(-5)` mol/L
C. `0.316 xx 10^(-5)` mol/L
D. `3.162 xx 10^(-8)` mol/L

Answer

To find the concentration of hydrogen ions \([H^+]\) from the given pH value of 4.5, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the pH Definition**:
The pH of a solution is defined as:
\[ \text{pH} = -\log[H^+] \]
where \([H^+]\) is the concentration of hydrogen ions in moles per liter.

2. **Set Up the Equation**:
Given that the pH is 4.5, we can set up the equation:
\[ 4.5 = -\log[H^+] \]

3. **Rearranging the Equation**:
To find \([H^+]\), we need to rearrange the equation:
\[ -4.5 = \log[H^+] \]

4. **Convert Logarithmic to Exponential Form**:
To eliminate the logarithm, we can rewrite the equation in exponential form:
\[ [H^+] = 10^{-4.5} \]

5. **Calculate the Value**:
Now, we can calculate \(10^{-4.5}\):
\[ [H^+] = 10^{-4.5} \approx 3.162 \times 10^{-5} \text{ moles per liter} \]

6. **Final Result**:
Thus, the concentration of hydrogen ions \([H^+]\) in the solution is:
\[ [H^+] \approx 3.162 \times 10^{-5} \text{ M} \]

### Summary:
The concentration of hydrogen ions in the solution with a pH of 4.5 is approximately \(3.162 \times 10^{-5} \text{ M}\).