Question

In the solid state reaction when MgO and F2O3 reacts to form MgFe2O4,it is clear found that the interfaces moved in the ratio of 1:2.7,close to the ideal value 1:3.This is can be described by which of the following mechanism in which the movement of the interfaces is used as a marker?

(a) Kirkedall Effect

(b) Grignard Reaction

(c) Michael Reaction

(d) Aldol Reaction

I have been asked this question in a national level competition.

The origin of the question is Solid State Reaction topic in section Preparative Methods of Solid State Chemistry

Answer 1

Right choice is (a) Kirkedall Effect

For explanation I would say: In the reaction such as the formation of the MgFe2O4, in which the interfaces between the reaction and the product can be clearly seen, perhaps due to a difference in color, the movement of the interfaces can be used as a marker to monitor the progress of the reaction. This effect of using a marker is known as the Kirkendall effect.