Question

Describe the Lux - Flood Concept.

Answer 1

Lux - Flood Concept (1939 & 1947) : 

(i) The proton plays an important role in explaining  the acid-base behaviour in the Bronsted-Lowery concept. Lux observed that acid - base reactions are also feasible in oxide systems without the aid of protons. 

(ii) Above approach was extended by Flood and applied to non-protonic systems, which were not covered by the Bronsted Lowery concept. 

(iii) According to this concept a base (like CaO, BaO or Na₂O) is an oxide ion (O^2–) donor and an acid (like SiO₂ , CO₂ or P₄ O₁₀) is an oxide ion (O^2–) acceptor.

(iv) Substances are termed amphoteric if they show a tendency of losing as well as accepting an oxide ion. 

Ex: ZnO, Al₂O₃ 

Note : 

(i) The concept is particularly applicable to reactions which take place at high temperature i.e. in metallurgical operations or during the manufacture of ceramics and glass. 

(ii) The approach can be extended to include other negative ion systems (like halides, sulphide or carbanion).