According to this concept acids are any chemical species which react with bases and gives cations or accept anions or electrons.
Similarly Bases are a chemical species which react with acids and gives anions or electrons or cations
Hard and Soft acids and bases:
The Lux-Flood concept is given by Lux in 1929 and supported by Flood in 1947. Lux-Flood concept is based on oxide ion acceptor and donor tendency.
Lux-Flood bases: According to this concept bases are
those species which can donate oxide ions examples.
Lux-Flood Acids: According to this concept Acids are
those species which can accept oxide ions.
Chemical Reactions according Lewis acid-base concept:
Acid-base reaction in term Lux-Flood acid and base is a specific reactions in which oxide ions are mainly use in molten form or at high temperature.
Amphoteric Nature of Oxides as per Lux-Flood Concept:
Acidic Nature of Xenon
fluoride as per Lux-Flood Concept:
According to Lux –Flood concept Xenon
fluorides accept oxide ions from other compounds and insert fluorides ions in
its place.
For examples
The Order of decreasing Lux-Flood acidity of Xenon Fluorides is given as:
Limitations of Lux-Flood Acid –base Concept:
(1) It is
dealing with anhydrous reaction in fused molten oxides and other high temperature reactions found in
metallurgy and ceramics.
(2) When
Lux-Flood, acidic and basic of oxide react with water gives corresponding acid
and base.
Limitations of Lux-Flood Acid
–base Concept:
(1) Base
must contain oxide ion and acid must have accept oxide ions.
(2)It
fails to explain reaction without metal
ions
The most common concept of
acids and bases is due to Cady and Elsey. Most of the solvents undergo
auto-ionization and form cation and anions like water, regardless it contains
protons or not for examples; H2O, NH3, H2SO4, HNO3, POCl3,
BrF3, N2O4, NOCl, CH3COOH,
Related Questions:
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Four-center two-electron bond (4C-2e Bond): Structure of AlCl3:
Electronegativity of F is much more than hydrogen and also hybridization of oxygen atoms in of H2O2 and O2F2 both have (sp3) same . According bent’s rule those hybrid orbitals containing flourine atom have less % s-characterand more p-character while other orbitals have more % s-character and less % s-character hence O-O bond length in O2F2 is shorter thane H2O2.
According to the bent's rule the more electronegative atom not only prefer to stay in that Hybride orbital which having less % S character (more p-character) but it also decreases % S-character and increases % P-character in its attached orbital from the central atom.
For example:C-H bond of CH4 is longer than C-H bond of floromethan
(CH3F) because In CH4 all the Sp3 hybrid orbitals are
equal in term of s-% character(25%) and %
p-charater(75%) so that all C-H bond in
CH4 are equal while in case
of CH3F the hybrid orbital has more p-character (more than 75%) and
less s-character (less then 25%) containg fluorine atom and other hybrid
orbitals have less p-character (less than75%) and more s-character (more than 25%)
hence C-H bond length of CH3F decreases.
EXCEPTIONS OF
BENT’S RULE:
(1):
Bent’s rule is applicable in those molecules where central
atoms are same and they are also in same
Hybridization.
For example N-N bond length cannot be compared in N2H4
and N2O4 using Bent rule.
(2): Bent’s rule violets in those molecules where steric
factor’s plays dominating rule.
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