1. What is Hydroxide Ion Concentration?

The hydroxide ion concentration ([OH-]) is a measure of the alkalinity of a solution. It's inversely related to the hydrogen ion concentration ([H+]) through the ion product of water (Kw).

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• \( [OH^-] \) — Hydroxide ion concentration (M)
• \( K_w \) — Ion product of water (1×10⁻¹⁴ M² at 25°C)
• \( [H^+] \) — Hydrogen ion concentration (M)

Explanation: The equation shows the inverse relationship between [OH-] and [H+] in aqueous solutions at a given temperature.

3. Importance of [OH-] Calculation

Details: Calculating hydroxide ion concentration is essential for determining pH, understanding acid-base chemistry, and in various chemical and biological processes.

4. Using the Calculator

Tips: Enter [H+] in molarity (M) and Kw in M². The default Kw value is 1×10⁻¹⁴ M² (standard at 25°C). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the relationship between [OH-] and pH?
A: pH = 14 - pOH, where pOH = -log[OH-]. Higher [OH-] means higher pH (more basic solution).

Q2: Does Kw change with temperature?
A: Yes, Kw increases with temperature. At 37°C (body temperature), Kw ≈ 2.4×10⁻¹⁴ M².

Q3: What is [OH-] in pure water at 25°C?
A: In pure water, [H+] = [OH-] = 1×10⁻⁷ M (pH = 7).

Q4: How does [OH-] relate to solution strength?
A: Higher [OH-] indicates a stronger base, just as higher [H+] indicates a stronger acid.

Q5: Can this calculator be used for non-aqueous solutions?
A: No, this equation is specific for aqueous solutions where Kw applies.