Equal volumes of solutions I and II with `[H^(+)] = 10^(-4)` M and `[OH^(-)] = 10^(-4)` M respectively are mixed. What will be the pH of the resulting solution ?

Options

A. 4
B. 10
C. 7
D. 0

Explanation

To find the pH of the resulting solution when equal volumes of solutions I and II are mixed, we can follow these steps:

### Step 1: Identify the concentrations of H⁺ and OH⁻ ions
- Solution I has a concentration of H⁺ ions: \([H^+] = 10^{-4} \, \text{M}\)
- Solution II has a concentration of OH⁻ ions: \([OH^-] = 10^{-4} \, \text{M}\)

### Step 2: Determine the nature of the resulting solution
When equal volumes of these two solutions are mixed, we need to compare the concentrations of H⁺ and OH⁻ ions:
- Since \([H^+] = [OH^-] = 10^{-4} \, \text{M}\), they are equal.

### Step 3: Conclude the type of solution
- When the concentration of H⁺ ions is equal to the concentration of OH⁻ ions, the solution is neutral.

### Step 4: Calculate the pH of the solution
- The pH of a neutral solution at 25°C is 7. Therefore, the pH of the resulting solution is:
\[ \text{pH} = 7 \]

### Final Answer
The pH of the resulting solution is **7**.

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