Multiple choice

What is the reason for this?

When a magnesium ribbon and a copper wire are wound around iron nails in two test tubes named A and B respectively, then  the tubes are left exposed to air for a few days, we notice that the iron nail in tube A does not rust but it rusts in the tube B.

  1. Copper prevents corrosion in tube A

  2. Reaction occurs between magnesium and copper

  3. Copper prevents corrosion in tube B

  4. Magnesium is more electropositive than iron
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Invar also known as FeNi36 is a nickel iron alloy notable for its uniquely low coefficient of thermal expansion (CTE or ل). The name comes from the word invariable referring to its lack of expansion or contraction with temperature changes.

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