Question

Identify the correct order of reactivity of metals among the following:
A.\[{\text{Cu}} < {\text{Fe}} < {\text{Zn}} < {\text{Al}} < {\text{Na}}\]
B.\[{\text{Fe}} < {\text{Zn}} < {\text{Cu}} < {\text{Na}} < {\text{Al}}\]
C.\[{\text{Zn}} < {\text{Cu}} < {\text{Fe}} < {\text{Al}} < {\text{Na}}\]
D.\[{\text{Cu}} < {\text{Zn}} < {\text{Al}} < {\text{Na < Fe}}\]

Answer 1

Hint: We must have the knowledge about properties of metals and the electrochemical series. There is a definite series that is obtained from the experimental data. It is based on the standard reduction potential values. Lower the reduction potential, higher is the reactivity.

Complete step by step answer:
Electrochemical series defines the arrangement of elements according to their respective electrode potential value. They are either arranged in increasing or decreasing order in electrochemical series
The values of electrode potential are calculated using standard hydrogen electrodes as reference. The potential value it shows is basically standard reduction potential. Metal always loses electrons and hence are electropositive in nature. Lower the standard reduction potential of an element, higher will be its oxidizing potential, higher will be its tendency to reduce other elements and oxidize itself hence it will lose electrons readily and will be a good metal. So if the electrochemical series is arranged in increasing order of the standard electrode potential then metals will be on the bottom half of the series, below hydrogen.
Hence, according to the electrochemical series the order is \[{\text{Cu}} < {\text{Fe}} < {\text{Zn}} < {\text{Al}} < {\text{Na}}\]
Some of the applications of Electrochemical Series are: To check the Oxidising and Reducing Strengths, for calculation of standard emf of a cell, to predict the spontaneity of Redox Reaction.

Hence the correct option is A.

Note:
Electrode potential is the ability of an element to lose or gain electrons when it is placed in the solution of its own ion. An element can even lose an electron or gain an electron, it depends on the nature of the element. A redox reaction is a reaction in which oxidation and reduction occurs simultaneously.