Hydrogen Half-Cell — Definition, Formula, Properties & Uses | AllChemicals | AllChemicals

Q: What is the formula for Hydrogen Half-Cell?

The formula or notation for Hydrogen Half-Cell is: 2H⁺ + 2e⁻ → H₂; E° = 0.00 V

Formula / Notation	2H⁺ + 2e⁻ → H₂; E° = 0.00 V
Also Known As	Standard hydrogen electrode (SHE), normal hydrogen electrode (NHE), hydrogen reference electrode

What is Hydrogen Half-Cell?

The standard hydrogen electrode (SHE), consisting of a platinum electrode in contact with 1 M H⁺ solution through which hydrogen gas at 1 atm is bubbled. It is assigned a standard electrode potential of exactly 0.00 V and serves as the universal reference electrode.

Formula & Notation

2H⁺ + 2e⁻ → H₂; E° = 0.00 V

Other Names / Synonyms: Standard hydrogen electrode (SHE), normal hydrogen electrode (NHE), hydrogen reference electrode

Properties & Characteristics

The hydrogen half-cell (Standard Hydrogen Electrode, SHE) is the universal reference electrode against which all standard electrode potentials are measured. It consists of a platinum black electrode in contact with H⁺ ions at unit activity (1 mol/L) with hydrogen gas at 1 atm pressure at 25°C. By convention, E°(SHE) = 0.000 V exactly. More positive E° than SHE means the electrode is a better oxidising agent; more negative means a better reducing agent.

Uses & Applications

The SHE is the reference for the entire electrochemical potential scale. It is used conceptually in all calculations involving standard electrode potentials. Practical reference electrodes (saturated calomel electrode SCE: +0.241 V vs SHE; Ag/AgCl: +0.197 V vs SHE) are used in laboratories because SHE is impractical.

Safety Information

The SHE uses flammable H₂ gas and concentrated H₂SO₄. Practical laboratory SHE setups require proper H₂ gas handling (ventilation, no ignition sources), acid-resistant construction, and careful sealing to prevent H₂ leakage.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Hydrogen Half-Cell

Formula 2H⁺ + 2e⁻ → H₂; E° = 0.00 V

Index All "H" terms

Synonyms Standard hydrogen electrode (SHE), normal hydrogen electrode (NHE), hydrogen reference electrode

Frequently Asked Questions

What is Hydrogen Half-Cell?

The standard hydrogen electrode (SHE), consisting of a platinum electrode in contact with 1 M H⁺ solution through which hydrogen gas at 1 atm is bubbled. It is assigned a standard electrode potential of exactly 0.00 V and serves as the universal reference electrode.

What is Hydrogen Half-Cell used for?

Is Hydrogen Half-Cell hazardous?

What is the formula for Hydrogen Half-Cell?

More "H" Terms

Haber Process N₂ + 3H₂ ⇌ 2NH₃ | ΔH = −92 kJ/mol Hafnium Hf Half Cell Half Life Half-Cell E = E° − (RT/nF)lnQ Half-Life A(t) = A₀e^(−λt); t½ = ln2/λ Half-Reaction Halide X⁻ (e.g., F⁻, Cl⁻, Br⁻, I⁻) Halogen F₂, Cl₂, Br₂, I₂, At; Group 17; ns²np⁵ valence configuration Halogenation C-X + Cl₂/Br₂ (hv or AlCl₃) → C-X(halogen); EAS or radical pathway Halogens Hard Acid Hard acid: small, highly charged, low polarisability (e.g., H⁺, Mg²⁺, Al³⁺)

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