The pH of blood serum is 7.4 . What is the hydrogen ion concentration of blood serum ?

Answer

To find the hydrogen ion concentration of blood serum given its pH, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the relationship between pH and hydrogen ion concentration**:
The pH of a solution is related to the hydrogen ion concentration \([H^+]\) by the formula:
\[ \text{pH} = -\log[H^+] \]

2. **Substitute the given pH value**:
We know that the pH of blood serum is 7.4. We can substitute this value into the formula:
\[ 7.4 = -\log[H^+] \]

3. **Rearrange to solve for \([H^+]\)**:
To find \([H^+]\), we need to isolate it. We can do this by taking the antilogarithm:
\[ [H^+] = 10^{-\text{pH}} = 10^{-7.4} \]

4. **Calculate \(10^{-7.4}\)**:
We can break this down further:
\[ 10^{-7.4} = 10^{-8} \times 10^{0.6} \]
Now we need to calculate \(10^{0.6}\):
\[ 10^{0.6} \approx 3.98 \]

5. **Combine the results**:
Now we can combine our results:
\[ [H^+] = 3.98 \times 10^{-8} \]

6. **Round the result**:
For simplicity, we can round this to:
\[ [H^+] \approx 4 \times 10^{-8} \, \text{M} \]

### Final Answer:
The hydrogen ion concentration of blood serum is approximately \(4 \times 10^{-8} \, \text{M}\).