Question

Which of the following pairs will give displacement reactions?
(A) NaCl solution and copper metal
(B) $MgC{{l}_{2}}$ solution and aluminium metal
(C) $FeS{{O}_{4}}$ solution and silver metal
(D) $AgN{{O}_{3}}$ solution and copper metal

Answer 1

In electrochemical series, the electrodes (metals and non-metals) in contact with their ions are arranged on the basis of the values of their standard reduction or oxidation potentials. Standard electrode potential is obtained by measuring the voltage when the half cell is connected to the standard hydrogen electrode under standard conditions.

Complete step by step solution:
Electrochemical series also sometimes referred to as activity series is a list that describes the arrangement of elements in order of their increasing electrode potential values. The series has been established by measuring the potential of various electrodes versus standard hydrogen electrodes (SHE).
Elements (other than hydrogen) that display a greater tendency to lose electrons to their solution are usually categorized as electropositive. Similarly, elements that acquire electrons are said to be electronegative. They are usually below the element hydrogen in the series. electropositive metals generally replace hydrogen from acids.
In the above given options, Copper metal and silver nitrate solution gives displacement reaction and the chemical equation can be written as:
$Cu+2AgN{{O}_{3}}\to Cu{{(N{{O}_{3}})}_{2}}+2Ag$
Silver in the electrochemical series is present below copper, therefore, it gets displaced by more reactive elements.

Hence the correct answer is the D option.
Note: Electrochemical series helps us to identify a good oxidizing agent or reducing agent. All the substance appearing on the top of the electrochemical series are a good oxidizing agent i.e., they have positive Value of standard reduction potential whereas those appearing on the bottom of the electrochemical series are a good reducing agent i.e., they have a negative value of standard reduction potential.