Question

Assertion: Copper is used to make hot water tanks and not steel (alloy of iron).
Reason: Copper does not react with cold water, hot water or steam. However, iron reacts with steam. If the hot water tanks are made up of steel, then iron would react vigorously with the steam formed from hot water.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

Hint:The gaseous phase of water is known as steam. It is also known as water vapor. It has a large amount of heat in it. Thus the chemical formula of steam is \[{{{H}}_2}{{O}}\]. The reaction between iron and water occurs only when the iron is in red hot form and water in steam form.

Complete step by step answer:
Chemically, iron is ${{Fe}}$. It does not have the ability to react with water under normal temperatures. Thus it is given high temperatures. Thus the iron is heated strongly till it becomes red hot.
Generally, alkali metals are reactive with water. The reaction is exothermic. It produces metal hydroxides and hydrogen molecules. But iron is not as reactive towards water as alkali metals. Thus it is provided with a large amount of heat. Usually, metals which have moderate reactivity react with steam to produce metal oxides and hydrogen gas. Therefore, iron produces iron oxide and hydrogen gas, when steam is passed over red hot iron.
The chemical reaction is given below:
${{3Fe}} + 4{{{H}}_2}{{O}}\xrightarrow{\Delta }{{F}}{{{e}}_3}{{{O}}_4} + 4{{{H}}_2}$
While copper is of low reactivity in the reactivity series of metals. Thus it does not react with cold water, hot water or steam. Its reactivity is even less than the reactivity of hydrogen. So it cannot be displaced.
Thus it is used for hot water tanks. The Reason is the correct explanation for the statement.

Hence, the correct option is A.

Note:
An important thing to note is that we should know about the reactivity series of metals. The reactivity series of metals is given below:
${{K}} > {{Na}} > {{Li}} > {{Ca}} > {{Mg}} > {{Zn}} > {{Fe}} > {{H}} > {{Cu}} > {{Au}}$. ${{K}}$, ${{Na}}$, ${{Li}}$ are alkali metals and ${{Ca}}$ and ${{Mg}}$ are alkaline earth metals.