Question

The metal which cannot displace hydrogen from acid is:
(A) iron
(B) copper
(C) sodium
(D) zinc

Answer 1

Hint: The reactivity series is a series of metals, in order of reactivity from highest to lowest. It is used to determine the products of single displacement reactions, whereby metal A will replace another metal B in a solution if A is higher in the series.

Complete step by step answer:
We have been provided with metals: iron, copper, sodium and zinc.
We need to tell which of them cannot displace hydrogen from acid,
So, for that:
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.
We know, that the metals which are more reactive than other metal displace them from their salt solution by displacement reaction,
The reactivity series lists metal compounds, including magnesium sulphur and lead, in their order of reactivity, with the least reactive at the top. Those at the top and bottom are most keen to react with other elements to form compounds. Less reactive metals will displace other metals from their compounds.
Now, as we know that iron, sodium and zinc are more reactive than hydrogen according to the hydrogen series but copper is less reactive than hydrogen.
So, we can say that copper would not be able to displace hydrogen from acid.
So, the correct answer is “Option B”.

Note: Despite being a non-metal, hydrogen is often included in the reactivity series since it helps compare the reactivities of the metals. The metals placed above hydrogen in the series can displace it from acids such as hydrochloric acid and sulphuric acid (since they are more reactive).