Ionic product of water increases, if

Options

A. `H^+` ions are added
B. OH ions are added
C. Temperature decreases
D. Temperature increases

Answer

To solve the question regarding the conditions under which the ionic product of water (Kw) increases, we can analyze the factors mentioned in the video transcript step by step.

### Step-by-Step Solution:

1. **Understanding Ionic Product of Water (Kw)**:
- The ionic product of water is defined as the product of the concentrations of hydrogen ions (H⁺) and hydroxide ions (OH⁻) in pure water at a given temperature.
- Mathematically, it is expressed as:
\[ K_w = [H^+][OH^-] \]
- At 25°C, Kw is approximately \(1.0 \times 10^{-14}\).

2. **Effect of Temperature**:
- The ionic product of water increases with an increase in temperature.
- For example, at 90°C, Kw is \(1.0 \times 10^{-12}\), indicating that both H⁺ and OH⁻ concentrations have increased.

3. **Adding H⁺ or OH⁻ Ions**:
- When H⁺ ions are added to water, the equilibrium shifts according to Le Chatelier's principle, resulting in an increase in the concentration of OH⁻ ions to maintain the equilibrium.
- Similarly, adding OH⁻ ions will increase the concentration of H⁺ ions. Thus, both actions lead to an increase in Kw.

4. **Effect of Decreasing Temperature**:
- Decreasing the temperature generally does not increase Kw; instead, it tends to decrease it. Therefore, this factor does not contribute to an increase in the ionic product of water.

5. **Conclusion**:
- The ionic product of water increases when:
- Temperature increases.
- H⁺ ions are added.
- OH⁻ ions are added.

### Final Answer:
The ionic product of water (Kw) increases if:
- Temperature increases.
- H⁺ ions are added.
- OH⁻ ions are added.