Q. 553.8( 12 Votes )
You are given samples of three metals-sodium, magnesium and copper. Suggest any two activities to arrange them in order of their decreasing reactivities.
1) When sodium, magnesium and copper are left in air, sodium reacts instantly with oxygen to form sodium oxide as it is a very reactive metal, magnesium reacts with oxygen to form magnesium oxide only on heating, whereas copper does not burn in air even on strong heating. It reacts only when the heating is done for a long time. By this we can say that sodium is most reactive, then magnesium and copper is the least reactive among the given three.
2) When Sodium reacts instantly with cold water it forms sodium hydroxide and hydrogen, magnesium does not react with cold water but it reacts with hot water to form magnesium hydroxide and hydrogen gas but on the other hand copper do not react even with steam. This shows that sodium is highly reactive; magnesium is less reactive than sodium and copper is the least reactive among the three.
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