Question

Name the following: A metal which does not react with cold water but reacts with steam.
(A) Magnesium
(B) Iron
(C) Zinc
(D) All of these

Answer 1

Hint: A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable or ductile. Metal reacts with water to give metal hydroxide and hydrogen gas.

Complete step by step answer:
We have been provided with metals: magnesium, iron, zinc,
We need to tell out of these metals which metal does not react with cold water but reacts with steam,
When water hits the metal, the metal releases electrons. These negatively charged particles generate heat as they leave the metal. Along the way, they also break apart the water molecules,
Out of the metal’s magnesium, iron and zinc,
Magnesium has almost no reaction with cold water. It reacts very slowly with hot water.  It reacts with steam when being heated and gives hydrogen gas and metal oxide,
     \[Mg+{{H}_ {2}} \to Mg{{(OH)} _ {2}} +{{H}_ {2}} \]
Zinc and iron do not react with cold or hot water.  They react with steam slowly to give the respective oxides,
     \[Zn+steam \to ZnO+{{H}_ {2}} \]
     \[Fe+steam \to FeO+{{H}_ {2}} \]
So, we can say that magnesium does not react with cold water but can react with steam,
Therefore, option (A) is correct.

Note: Beryllium (Be) is the only alkaline earth metal that does not react with water or steam, even if metal is heated to red heat. Additionally, beryllium has a resistant outer oxide layer that lowers its reactivity at lower temperatures.