Chemistry Solids UHS 2024
PMDC Verified Question 1 of 54
Whenever the crystalline solids are broken they do so along definite planes known as:
A
Cleavage plane
B
Refractory planes
C
Sagittal planes
D
Coronal planes
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Cleavage plane
Concept:
Crystalline solids feature highly ordered, repeating arrangements of atoms. Because of this geometry, there are specific directions where the bonds holding the lattice together are weaker.

Solution:
  • When stress or force is applied to a crystalline solid, it will naturally split or break along these specific, well-defined directional planes of weakness.
  • These flat, smooth surfaces that result from the break are scientifically termed cleavage planes.
  • This property is a hallmark of crystallinity, distinguishing them from amorphous solids, which shatter irregularly (conchoidal fracture).


Why other options are incorrect:
  • B: Refractory refers to materials highly resistant to heat, not structural breaking planes.
  • C, D: Sagittal and Coronal planes are anatomical terms used to describe cross-sections of the human body, completely irrelevant to solid-state chemistry.

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