Electrolysis Gas Volume Calculator

Compute the volume of gas produced at an electrode during electrolysis using Faraday's laws and the ideal gas law. For students, researchers, and lab technicians. Supports units: A, C, mol, s/min/h, K/°C/°F, atm/bar/kPa/torr, L/mL. Runs entirely offline in your browser.

Educational only. Follow your lab SOPs and SDS.

Current (I)

e.g., 0.5, 2e-3

Duration (t)

e.g., 3600, 1.5e3

Gas Produced

Temperature (T)

Pressure (P)

Current Efficiency (%)

100% for ideal Faraday efficiency

Decimal Places

Results

Gas Volume (V)

0.000 L

Intermediate Values

Total Charge (Q): 0.000 C
Moles of Gas (n): 0.000 mol
Temperature (T): 0.00 K
Pressure (P): 0.000 atm

Understanding Electrolysis Gas Volume

Why This Matters

Predicting gas volume from electrolysis is essential for designing electrochemical cells, estimating production rates in industrial processes (e.g., chlor‑alkali, hydrogen generation), and verifying Faraday's law in teaching labs. Accurate calculation helps in sizing gas collection equipment and ensuring safety.

How to Use This Tool

Enter the current (DC) and duration of electrolysis.
Select the gas produced (or enter custom n‑factor).
Set the temperature and pressure of the collected gas.
Adjust efficiency if known (100% for ideal Faraday efficiency).
Click "Calculate Volume". Use "Swap: Find Current" to reverse the calculation.

Realistic Examples

Scenario	Inputs	Volume Result
Lab electrolysis of water (H₂)	I = 0.5 A, t = 30 min, T = 25°C, P = 1 atm, n=2	0.116 L H₂
Industrial chlorine production	I = 5000 A, t = 1 h, T = 70°C, P = 1.2 bar, n=2, efficiency=95%	87.1 L Cl₂
O₂ at high altitude	I = 0.1 A, t = 2 h, T = 10°C, P = 0.8 atm, n=4	0.042 L O₂

Common Mistakes Checklist

Using the wrong n‑factor (e.g., 1 for H₂ instead of 2).
Not converting time to seconds when using Faraday's constant in C/mol.
Forgetting to convert temperature to Kelvin for the ideal gas law.
Ignoring current efficiency (faradaic efficiency) in real cells.
Assuming ideal gas behavior at high pressure or near condensation.

Quick Gas Volume Converter

From Value

From Unit

To Unit

Converted Volume

1.000 L

Frequently Asked Questions

What are the assumptions and limits of this calculator?

Assumes ideal gas behavior, 100% Faraday efficiency (unless adjusted), and no side reactions. The ideal gas law becomes inaccurate at high pressures (>10 atm) or near the gas's condensation point. For precise work, use an equation of state (e.g., van der Waals).

How do I determine the n‑factor for a custom reaction?

n is the number of electrons transferred per molecule of gas produced. Write the balanced half‑reaction for the electrode where the gas forms. Example: For bromine (Br₂) from Br⁻: 2Br⁻ → Br₂ + 2e⁻, so n=2.

Why is my experimental volume lower than calculated?

Common reasons: current efficiency <100% (side reactions, parasitic currents), gas solubility in the electrolyte, leaks in collection apparatus, or non‑ideal temperature/pressure measurement. Always measure gas volume under dry, defined conditions.

What safety precautions are needed for electrolysis gas collection?

Hydrogen and oxygen mixtures are explosive; keep them separated or vented. Chlorine is toxic; use a fume hood. Always wear appropriate PPE (gloves, goggles), and ensure electrical isolation. Follow SDS for all chemicals and gases involved.

Formulas & Assumptions

Faraday's law: n = (I · t · η) / (F · z) where n = moles of gas, I = current (A), t = time (s), η = efficiency (decimal), F = 96485.33212 C/mol, z = n‑factor.
Ideal gas law: V = (n · R · T) / P where V = volume (L), R = 0.08205746 L·atm/(mol·K), T in Kelvin, P in atm.
Unit conversions: Built‑in for current (1 A = 1000 mA), time (1 h = 3600 s, 1 min = 60 s), temperature (°C → K = °C + 273.15, °F → K = (°F − 32) × 5/9 + 273.15), pressure (1 atm = 1.01325 bar = 101.325 kPa = 760 torr).
Rounding: Results rounded to the selected decimal places; intermediate values keep higher precision.

For informational and educational purposes only. Estimates depend on your inputs and simplifying assumptions. This tool does not replace professional judgment, lab SOPs, or safety procedures. Always follow SDS guidance and institutional policies.

Sources & References: Common chemistry constants: R, F; Standard unit conversions and lab measurement best practices; General analytical chemistry and uncertainty concepts; Electrochemistry principles (Faraday's laws, ideal gas); Laboratory safety basics and SDS principles.

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Electrolysis Gas Volume Calculator

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