Inaugurated by IN-SPACe
ISRO Registered Space Tutor
S4-SA2-0753
What is a Displacement Reaction (one element replaces another)?
Grade Level:
Class 6
Space Technology, EVs, Climate Change, Biotechnology, HealthTech, Robotics, Chemistry, Physics
Definition
What is it?
A displacement reaction is a chemical reaction where a more reactive element kicks out a less reactive element from its compound. Think of it like a stronger player replacing a weaker player in a team. The stronger element 'displaces' or takes the place of the weaker one.
Simple Example
Quick Example
Imagine you have a cricket team (Compound) with a good batsman (Element A) and a not-so-good bowler (Element B). A new, much better bowler (Element C) joins. The team might replace the not-so-good bowler (Element B) with the new, better bowler (Element C). Here, the better bowler (C) displaces the weaker bowler (B) from the team.
Worked Example
Step-by-Step
Let's look at a chemical example: When iron nails are dipped in copper sulphate solution.
Step 1: Identify the elements involved. We have Iron (Fe) and Copper (Cu).
---Step 2: Identify the compound. Copper sulphate (CuSO4) is the compound.
---Step 3: Compare their reactivity. Iron is more reactive than Copper.
---Step 4: The more reactive element (Iron) will displace the less reactive element (Copper) from its compound (Copper sulphate).
---Step 5: The iron takes the place of copper, forming iron sulphate. Copper is left behind.
---Answer: Iron + Copper Sulphate → Iron Sulphate + Copper (Fe + CuSO4 → FeSO4 + Cu). The blue copper sulphate solution turns green due to iron sulphate, and reddish-brown copper deposits on the iron nail.
Why It Matters
Displacement reactions are super important in making new materials and extracting metals. They are used in processes like refining metals for EVs and making parts for Robotics. Knowing this helps engineers in Chemistry and Metallurgy create useful products and understand how different substances interact.
Common Mistakes
MISTAKE: Thinking any element can displace another from a compound. | CORRECTION: Only a MORE reactive element can displace a LESS reactive element. Reactivity order matters!
MISTAKE: Confusing displacement with combination or decomposition reactions. | CORRECTION: In displacement, one element replaces another. In combination, two or more substances combine. In decomposition, one substance breaks down.
MISTAKE: Not identifying the correct products after displacement. | CORRECTION: The displaced element will be alone, and the displacing element will form a new compound with the remaining part of the original compound.
Practice Questions
Try It Yourself
QUESTION: Zinc (Zn) is more reactive than Copper (Cu). What happens when Zinc metal is added to Copper Sulphate (CuSO4) solution? | ANSWER: Zinc displaces Copper from Copper Sulphate to form Zinc Sulphate (ZnSO4) and Copper (Cu). (Zn + CuSO4 → ZnSO4 + Cu)
QUESTION: Can Silver (Ag) displace Copper (Cu) from Copper Nitrate (Cu(NO3)2) solution, if Copper is more reactive than Silver? Explain why or why not. | ANSWER: No, Silver cannot displace Copper. This is because Silver is less reactive than Copper, and only a more reactive element can displace a less reactive one.
QUESTION: A student observes that when a shiny grey metal 'X' is put into a blue solution of 'Y' sulphate, the solution turns colourless and a reddish-brown solid 'Y' appears. Identify the type of reaction and which element is more reactive. | ANSWER: This is a displacement reaction. Element 'X' is more reactive than element 'Y' because 'X' has displaced 'Y' from its sulphate solution.
MCQ
Quick Quiz
Which of the following is an example of a displacement reaction?
H2 + O2 → H2O
CaCO3 → CaO + CO2
Mg + CuSO4 → MgSO4 + Cu
NaCl + AgNO3 → AgCl + NaNO3
The Correct Answer Is:
C
Option C shows Magnesium (Mg) displacing Copper (Cu) from Copper Sulphate (CuSO4) because Mg is more reactive than Cu. Options A and B are combination and decomposition reactions, respectively. Option D is a double displacement reaction.
Real World Connection
In the Real World
In India, displacement reactions are crucial in extracting pure metals like iron and copper from their ores. For example, in steel plants, iron is extracted using displacement principles. This pure iron is then used to build everything from auto-rickshaws to parts for ISRO rockets and even our kitchen utensils.
Key Vocabulary
Key Terms
REACTIVE: How easily an element forms chemical bonds or takes part in reactions. | DISPLACE: To take the place of something or someone. | COMPOUND: A substance formed when two or more chemical elements are chemically bonded together. | ELEMENT: A pure substance consisting only of atoms that all have the same numbers of protons in their nuclei.
What's Next
What to Learn Next
Great job understanding displacement reactions! Next, you should learn about the 'Reactivity Series' of metals. This series will help you predict which elements can displace others, making you a pro at understanding these reactions!
