Question

Which of the following reactions is not a metal displacement reaction?

• A. \(2 Mg(s) + TiCl_4(l) \rightarrow 2 MgCl_2(s) + Ti(s)\)
• B. \(2 Al(s) + Cr_2O_3(s) \rightarrow Al_2O_3(s) + 2 Cr(s)\)
• C. \(5 Ca(s) + V_2O_5(s) \rightarrow 5 CaO(s) + 2 V(s)\)
• D. \(2 Fe(s) + 3 H_2O(l) \rightarrow Fe_2O_3(s) + 3 H_2(g)\)

Hint:

Remember that a metal displacement reaction involves one metal replacing another metal in a compound. Reactions involving simple combination or decomposition without displacement of metals are not considered metal displacement reactions.

Answer 1

The Correct Option is D

The correct answer is (4) \( 2\text{Fe(s)} + 3\text{H}_2\text{O(l)} \rightarrow \text{Fe}_2\text{O}_3\text{(s)} + 3\text{H}_2\text{(g)} \). 
Metal Displacement Reactions:

In a metal displacement reaction, a more reactive metal displaces a less reactive metal from its compound. This is based on the activity series of metals.

Analysis of the Reactions: 
(1) \( 2\text{Mg(s)} + \text{TiCl}_4\text{(l)} \rightarrow 2\text{MgCl}_2\text{(s)} + \text{Ti(s)} \): Magnesium (Mg) is more reactive than titanium (Ti), so it displaces Ti from its chloride. This is a metal displacement reaction. 
(2) \( 2\text{Al(s)} + \text{Cr}_2\text{O}_3\text{(s)} \rightarrow \text{Al}_2\text{O}_3\text{(s)} + 2\text{Cr(s)} \): Aluminum (Al) is more reactive than chromium (Cr), so it displaces Cr from its oxide. This is a metal displacement reaction. 
(3) \( 5\text{Ca(s)} + \text{V}_2\text{O}_5\text{(s)} \rightarrow 5\text{CaO(s)} + 2\text{V(s)} \): Calcium (Ca) is more reactive than vanadium (V), so it displaces V from its oxide. This is a metal displacement reaction. 
(4) \( 2\text{Fe(s)} + 3\text{H}_2\text{O(l)} \rightarrow \text{Fe}_2\text{O}_3\text{(s)} + 3\text{H}_2\text{(g)} \): In this reaction, iron (Fe) reacts with water (H$_2$O) to form iron oxide (Fe$_2$O$_3$) and hydrogen gas (H$_2$). This is not a metal displacement reaction. It is a redox reaction where iron is oxidized, and hydrogen is reduced. 
Key Point: Metal displacement reactions specifically involve one metal replacing another metal in a compound.

Answer 2

To solve this problem, we need to identify which of the given reactions is not a metal displacement reaction.

1. Understanding Metal Displacement Reactions:
In a metal displacement reaction, a more reactive metal displaces a less reactive metal from its compound. This type of reaction typically occurs in aqueous solutions where one metal replaces another, as seen in single-replacement reactions.

2. Analyzing Each Reaction:

Option A: 2Mg(s) + TiCl₄(l) → 2MgCl₂(s) + Ti(s)
This is a metal displacement reaction where magnesium (Mg), a more reactive metal, displaces titanium (Ti) from its chloride compound.

Option B: 2Al(s) + Cr₂O₃(s) → Al₂O₃(s) + 2Cr(s)
This is also a metal displacement reaction where aluminum (Al) displaces chromium (Cr) from its oxide.

Option C: 5Ca(s) + V₂O₅(s) → 5CaO(s) + 2V(s)
This is a metal displacement reaction where calcium (Ca) displaces vanadium (V) from its oxide.

Option D: 2Fe(s) + 3H₂O(l) → Fe₂O₃(s) + 3H₂(g)
This is not a metal displacement reaction. It is a redox reaction where iron (Fe) reacts with water (H₂O) to form iron oxide (Fe₂O₃) and hydrogen gas (H₂), but there is no displacement of one metal by another. This reaction is more of an oxidation-reduction reaction.

3. Conclusion:
The correct answer is Option D, as it does not involve a metal displacing another metal.

Final Answer:
The correct answer is Option D: 2Fe(s) + 3H₂O(l) → Fe₂O₃(s) + 3H₂(g).