Standard electrode potentials — the electrochemical seriesमानक इलेक्ट्रोड विभव — विद्युत-रासायनिक श्रेणीStandard electrode potentials — the electrochemical series
NCERT Table 2.1 · Class 12 Chemistry · Chapter 2 · interactive diagram
Parts and what they mean
- F₂(g) + 2e⁻ → 2F⁻, E° = +2.87 V (F₂(g) + 2e⁻ → 2F⁻, E° = +2.87 V) — Highest E°: F₂ is the strongest oxidising agent; F⁻ is the weakest reducing agent.
- MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O, E° = +1.51 V (MnO₄⁻/Mn²⁺, E° = +1.51 V) — Acidified permanganate is a strong oxidising agent.
- Cl₂(g) + 2e⁻ → 2Cl⁻, E° = +1.36 V (Cl₂/Cl⁻, E° = +1.36 V) — Used again when predicting products of electrolysis of brine.
- Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O, E° = +1.33 V (Cr₂O₇²⁻/Cr³⁺, E° = +1.33 V) — Acidified dichromate — another strong oxidising agent.
- Ag⁺ + e⁻ → Ag(s), E° = +0.80 V (Ag⁺/Ag, E° = +0.80 V) — Positive E°: Ag⁺ is reduced more easily than H⁺.
- Cu²⁺ + 2e⁻ → Cu(s), E° = +0.34 V (Cu²⁺/Cu, E° = +0.34 V) — Positive E°, so H⁺ cannot oxidise Cu — copper does not dissolve in HCl (nitrate ion oxidises it in HNO₃).
- 2H⁺ + 2e⁻ → H₂(g), E° = 0.00 V (reference) (2H⁺/H₂, E° = 0.00 V (संदर्भ)) — Every other E° is measured against the standard hydrogen electrode.
- Zn²⁺ + 2e⁻ → Zn(s), E° = −0.76 V (Zn²⁺/Zn, E° = −0.76 V) — Negative E°: H⁺ ions can oxidise zinc (zinc can reduce H⁺).
- Mg²⁺ + 2e⁻ → Mg(s), E° = −2.36 V (Mg²⁺/Mg, E° = −2.36 V) — Very reactive; used as a sacrificial electrode to protect iron.
- Li⁺ + e⁻ → Li(s), E° = −3.05 V (Li⁺/Li, E° = −3.05 V) — Lowest E°: Li⁺ is the weakest oxidising agent and lithium metal the most powerful reducing agent in aqueous solution.
- Oxidising power increases upwards (ऊपर की ओर ऑक्सीकारक क्षमता बढ़ती है) — The species on the LEFT (oxidised form) becomes a stronger oxidising agent as E° increases.
- Reducing power increases downwards (नीचे की ओर अपचायक क्षमता बढ़ती है) — The species on the RIGHT (reduced form) becomes a stronger reducing agent as E° decreases.
Original diagram drawn by Simple Learning Hub, based on NCERT Table 2.1. Report a mistake