The H ion concentration of a solution is `4.75xx10^(-5)`M. Then the OH ion concentration of the same solution is

Options

A. `4xx10^(-5)` M
B. `2.5 xx10^(9)` M
C. `1.0xx10^(7)` M
D. `2.5xx10^(-10)` M

Answer

To find the hydroxide ion concentration \([OH^-]\) in a solution when the hydrogen ion concentration \([H^+]\) is given, we can use the ion product constant of water (\(K_w\)). The relationship is given by:

\[ K_w = [H^+][OH^-] \]

At 25°C, \(K_w\) is equal to \(1.0 \times 10^{-14}\).

### Step-by-Step Solution:

1. **Identify the given values**:
- The hydrogen ion concentration \([H^+]\) is given as \(4.75 \times 10^{-5} \, M\).

2. **Write the equation for the ion product constant**:
\[ K_w = [H^+][OH^-] \]
Substituting the known value of \(K_w\):
\[ 1.0 \times 10^{-14} = [H^+][OH^-] \]

3. **Rearrange the equation to solve for \([OH^-]\)**:
\[ [OH^-] = \frac{K_w}{[H^+]} \]

4. **Substitute the known values into the equation**:
\[ [OH^-] = \frac{1.0 \times 10^{-14}}{4.75 \times 10^{-5}} \]

5. **Perform the calculation**:
\[ [OH^-] = \frac{1.0 \times 10^{-14}}{4.75 \times 10^{-5}} \approx 2.11 \times 10^{-10} \, M \]

### Final Answer:
The hydroxide ion concentration \([OH^-]\) is approximately \(2.11 \times 10^{-10} \, M\).