Question

If an allotropic form changes slowly to a stable form. It is called:

• A. enantiotropy
• B. dynamic allotropy
• C. monotropy
• D. none of the above

Answer 1

Answer: (C)

monotropy

(i) Enantiotropy: When two forms of a solid substance exist together in equilibrium with each other at a particular temperature under normal pressure eg, $S_R\rightleftharpoons S_M$
(ii) Dynamic allotropy: If different allotropic forms exists in equilibrium over a range of temperature.
(iii) Monotropy: If an allotropic form changes slowly to a stable form. eg,
$O_3\to O_2$
$\therefore$ Monotropy is correct answer.