Percent Ionization Calculator For Water

Percent Ionization Formula:

\[ \% \text{ Ionization} = \sqrt{\frac{K_w}{[H_2O]}} \times 100 \approx 1.8 \times 10^{-7} \% \]

Percent Ionization:

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1. What is Percent Ionization of Water?

The percent ionization of water represents the fraction of water molecules that dissociate into hydrogen (H⁺) and hydroxide (OH⁻) ions at equilibrium. For pure water at 25°C, this value is approximately 1.8 × 10⁻⁷%, indicating that water is a very weak electrolyte.

2. How Does the Calculator Work?

The calculator uses the percent ionization formula:

\[ \% \text{ Ionization} = \sqrt{\frac{K_w}{[H_2O]}} \times 100 \]

Where:

\( K_w \) — Water ionization constant (typically 1×10⁻¹⁴ mol²/L² at 25°C)
\( [H_2O] \) — Concentration of water (typically 55.5 mol/L for pure water)

Explanation: The formula calculates the square root of the ratio between the ionization constant and water concentration, then multiplies by 100 to express as a percentage.

3. Importance of Percent Ionization Calculation

Details: Understanding water's ionization is fundamental to acid-base chemistry, pH calculations, and comprehending the behavior of aqueous solutions. It helps explain why pure water has a neutral pH of 7 at 25°C.

4. Using the Calculator

Tips: Enter the water ionization constant (K_w) in mol²/L² and water concentration in mol/L. Standard values are pre-filled (K_w = 1×10⁻¹⁴, [H₂O] = 55.5).

5. Frequently Asked Questions (FAQ)

Q1: Why is the percent ionization of water so small?
A: Water has a very strong O-H bond, making it difficult to dissociate. The equilibrium strongly favors the associated water molecules over the dissociated ions.

Q2: How does temperature affect water ionization?
A: Increasing temperature increases both K_w and percent ionization. K_w reaches approximately 10⁻¹² at 100°C.

Q3: What is the typical concentration of water used in calculations?
A: For pure water at 25°C, the concentration is 55.5 mol/L, calculated from water's density (1 g/mL) and molar mass (18 g/mol).

Q4: Can this calculation be applied to other solvents?
A: The same principle applies, but each solvent has its own autoionization constant and concentration that must be used in the formula.

Q5: Why is this calculation important in chemistry?
A: It provides the fundamental basis for understanding pH, acid-base equilibria, and the behavior of ions in aqueous solutions.