How to Figure out Relative Oxidizing Power of Molecules or Ions – Part 3

Redox or reduction–oxidation or oxidation–reduction (simultaneous) is a type of chemical reaction in which the oxidation states (OSs) of the reactants change.


Mnemonic: OIL RIG (Oxidation Is Loss, Reduction Is Gain)

Redox potential aka oxidation/reduction potential (ORP or Ered) is a measure of the tendency of a chemical species to gain electrons from or lose electrons to an electrode; and therefore, be reduced or oxidized respectively.

As per the IUPAC (international union of pure and applied chemistry), standard electrode potential (EѲ) is the value of the standard emf (electromotive force) of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-hand electrode.

Question:

For the first-row transition metals the EѲ values are:

E0 (V)

V

Cr

Mn

Fe

Co

Ni

Cu

(M2+/M)

–1.18

– 0.91

–1.18

– 0.44

– 0.28

– 0.25

+0.34

Explain the irregularity in the above values.

Solution:



Click/tap to enlarge the image

Ionization energy/enthalpy/potential (IE) is the minimum energy required to remove the most labile electron(s) (the valence electron(s)) of an isolated gaseous atom, positive ion, or molecule.

Tricky transition metals❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com❗

References:

(1)    Ncert. Chemistry : Textbook for Class XII - Part.I; National Council Of Educational Research And Training: New Delhi.

‌(2)    Brown, C.; Ford, M. Higher Level Chemistry, 2nd ed.; Pearson Education: Harlow, Essex, 2014.

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