Observed E°(M²⁺/M) values of the 3d metals3d धातुओं के प्रेक्षित E°(M²⁺/M) मानObserved E°(M²⁺/M) values of the 3d metals

Class 12 Chemistry · Chapter 4 · interactive diagram

Parts and what they mean

• General trend: less negative (सामान्य प्रवृत्ति: कम ऋणात्मक) — Across the series E° becomes less negative, mainly because ionisation enthalpies (IE₁ + IE₂) increase.
• Cu: +0.34 V (Cu: +0.34 V) — Unique positive value: high atomisation enthalpy + high IE₂ are not balanced by its hydration enthalpy. Cu does not liberate H₂ from acids.
• Mn and Zn: more negative (Mn और Zn: अधिक ऋणात्मक) — Stability of half-filled d⁵ (Mn²⁺) and filled d¹⁰ (Zn²⁺) makes their E° more negative than expected.
• Zn: −0.76 V (Zn: −0.76 V) — Zn²⁺ is d¹⁰ — the stable configuration pulls E° down.
• Ni: −0.25 V (Ni: −0.25 V) — NCERT: Ni is more negative than expected because of its highest negative hydration enthalpy.

Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake