Chemistry S & P Block Elements MDCAT 2011
PMDC Verified Question 102 of 104
When the elements of group II-A are exposed to air, they quickly become coated with layer of oxide. What is the purpose of this oxide layer
A
The oxide layer exposes the metal to atmospheric attack
B
The oxide layer increases the reactivity of metal
C
The oxide layer protects the metal from further attack
D
No layer forms
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: The oxide layer protects the metal from further attack
Concept:

Certain metals form a non-porous, highly stable metal oxide layer on their surface when exposed to atmospheric oxygen. This process is known as passivation.

Solution:

  • Group II-A elements (like Beryllium and Magnesium) are reactive and quickly form an oxide layer (e.g., BeO, MgO) upon exposure to air.
  • This stable, impermeable oxide layer adheres tightly to the metal surface.
  • It acts as a physical barrier, effectively protecting the underlying unreacted metal from further oxidation or chemical attack.


Why other options are incorrect:

  • Option A & B: The layer restricts, rather than exposes or increases, reactivity with the atmosphere.
  • Option D: A layer definitively forms due to the high reactivity of these alkaline earth metals with oxygen.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

Previous Question All S & P Block Elements MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App