Question

Soldiers of Napolean army which at Alps during freezing winter suffered a serious problem as regards to the tin buttons of their uniforms. White metallic tin buttons got covered by grey powder. This transformation is related to:

• A. an interaction with nitrogen of the air at very low temperature
• B. a change in the partial pressure of oxygen in the air
• C. a change in the crystalline structure of tin
• D. an interaction with water vapour contained in the humid air

Answer 1

The correct option is C a change in the crystalline structure of tin

The transformation in the above question is due to the change in crystalline structure. At $13.2°C$ $\left(about56°F\right)$ and below, pure tin transforms from the silvery, ductile metallic allotrope of $\beta -form$ white tin to brittle, nonmetallic, $\alpha -form$ grey tin with a diamond cubic structure.

Hence option C is correct.