1. What is Hydroxide Ion Concentration?

The hydroxide ion concentration ([OH-]) is a measure of the alkalinity of a solution. It's related to the hydrogen ion concentration ([H+]) through the water dissociation constant (Kw), which is temperature-dependent.

2. How Does the Calculator Work?

The calculator uses the equation:

Where:

• \( [OH^-] \) — Hydroxide ion concentration (mol/L)
• \( K_w(T) \) — Temperature-dependent water dissociation constant (mol²/L²)
• \( [H^+] \) — Hydrogen ion concentration (mol/L)

Explanation: The equation shows the inverse relationship between [OH-] and [H+] in aqueous solutions, mediated by the water dissociation constant which varies with temperature.

3. Importance of [OH-] Calculation

Details: Calculating hydroxide ion concentration is essential for understanding solution pH, buffer capacity, and chemical reaction conditions in various fields including chemistry, biology, and environmental science.

4. Using the Calculator

Tips: Enter hydrogen ion concentration in mol/L and temperature in °C. The calculator will determine Kw at the given temperature and compute [OH-].

5. Frequently Asked Questions (FAQ)

Q1: What is the relationship between [OH-] and pH?
A: pH = -log[H+], while pOH = -log[OH-]. In aqueous solutions at 25°C, pH + pOH = 14.

Q2: How does temperature affect Kw?
A: Kw increases with temperature as water dissociation is endothermic. At 25°C, Kw = 1.0×10⁻¹⁴, but at 37°C (body temp), Kw ≈ 2.4×10⁻¹⁴.

Q3: What are typical [OH-] values in common solutions?
A: In neutral water at 25°C, [OH-] = 1×10⁻⁷ M. In 0.1 M NaOH, [OH-] ≈ 0.1 M.

Q4: Can this calculator be used for very high or low temperatures?
A: The calculator uses a simplified temperature adjustment. For extreme temperatures, more precise Kw values should be used.

Q5: How is [OH-] measured experimentally?
A: Common methods include pH meters (converted to [OH-] via Kw), conductivity measurements, or acid-base titration.