Understanding Feasible Chemical Reactions

A chemical reaction is considered feasible under normal conditions if it can proceed spontaneously. In the case of single displacement reactions involving metals, the feasibility depends on the relative reactivity of the metals involved. A more reactive metal can displace a less reactive metal from its salt solution. This concept is governed by the reactivity series of metals.

The Reactivity Series of Metals

The reactivity series is a list of metals arranged in order of their decreasing reactivity. Metals higher up in the series are more reactive than those lower down. Here is a part of the reactivity series relevant to the metals in the given options, ordered from most reactive to least reactive:

For a single displacement reaction \( A + BC \rightarrow AC + B \) to occur, metal A must be more reactive than metal B.

Analyzing Each Chemical Reaction Option

Let's examine each provided chemical reaction based on the reactivity series:

• Option 1: \($ Fe + CuSO_4 \rightarrow FeSO_4 + Cu $\)

  This reaction involves Iron (Fe) and Copper (Cu). Looking at the reactivity series, Iron (Fe) is placed above Copper (Cu). This means Iron is more reactive than Copper. Therefore, Iron can displace Copper from Copper sulphate solution. This reaction is feasible.

• Option 2: \($ Zn + CuSO_4 \rightarrow ZnSO_4 + Cu $\)

  This reaction involves Zinc (Zn) and Copper (Cu). In the reactivity series, Zinc (Zn) is placed above Copper (Cu). This indicates that Zinc is more reactive than Copper. Thus, Zinc can displace Copper from Copper sulphate solution. This reaction is feasible.

• Option 3: \($ Cu + PbCl_2 \rightarrow CuCl_2 + Pb $\)

  This reaction involves Copper (Cu) and Lead (Pb). According to the reactivity series, Copper (Cu) is placed below Lead (Pb). This means Copper is less reactive than Lead. Therefore, Copper cannot displace Lead from Lead chloride solution. This reaction is NOT feasible.

• Option 4: \($ Mg + CuSO_4 \rightarrow MgSO_4 + Cu $\)

  This reaction involves Magnesium (Mg) and Copper (Cu). In the reactivity series, Magnesium (Mg) is placed significantly above Copper (Cu), indicating it is much more reactive than Copper. Thus, Magnesium can displace Copper from Copper sulphate solution. This reaction is feasible.

Identifying the Non-Feasible Reaction

Based on the analysis using the reactivity series, the reaction where a less reactive metal is attempting to displace a more reactive metal from its salt solution is not feasible. This is the case in Option 3: \($ Cu + PbCl_2 \rightarrow CuCl_2 + Pb $\), because Copper is less reactive than Lead.

Revision Table: Reactivity Comparison for Feasibility

Additional Information: Factors Affecting Reactivity

While the reactivity series is a primary tool for predicting single displacement reactions in solutions, other factors can sometimes influence reactivity under different conditions, such as temperature or concentration. The position of a metal in the reactivity series is related to its tendency to lose electrons and form positive ions (oxidation). More reactive metals lose electrons more easily.