1. What is H+ Ion Concentration?

The H+ ion concentration ([H+]) is a measure of the acidity of a solution. In lemon juice with pH 2.40, the [H+] is approximately 0.004 mol/L, indicating high acidity.

2. How Does the Calculator Work?

The calculator uses the pH formula:

Where:

• \( [H^+] \) — Hydrogen ion concentration (mol/L)
• \( pH \) — Negative logarithm of H+ concentration

Explanation: The pH scale is logarithmic, meaning each whole pH value below 7 is ten times more acidic than the next higher value.

3. Importance of pH and [H+]

Details: Knowing the exact H+ concentration is important in food science, biochemistry, and industrial processes where precise acidity control is needed.

4. Using the Calculator

Tips: Enter the pH value (default is 2.40 for lemon juice). The calculator will compute the corresponding H+ ion concentration in moles per liter (mol/L).

5. Frequently Asked Questions (FAQ)

Q1: Why is lemon juice so acidic?
A: Lemon juice contains about 5-6% citric acid, which dissociates in water to release H+ ions, giving it a low pH around 2.40.

Q2: How does this compare to other common acids?
A: Gastric acid (pH ~1.5-3.5), vinegar (pH ~2.4-3.4), and orange juice (pH ~3.3-4.2) have similar acidity ranges.

Q3: What's the relationship between pH and [H+]?
A: pH = -log[H+], so [H+] = 10^(-pH). A pH difference of 1 unit means a 10-fold difference in [H+].

Q4: Why use scientific notation for [H+]?
A: H+ concentrations in aqueous solutions are typically very small numbers (e.g., 0.0000001 mol/L for pH 7), so scientific notation is more convenient.

Q5: Can I calculate [OH-] from this?
A: Yes, using the water dissociation constant Kw = [H+][OH-] = 1×10^(-14) at 25°C, you can calculate [OH-] = Kw/[H+].