This activity 1.3 helps students understand the reaction between a metal and an acid. This activity demonstrates both displacement reaction and exothermic reaction which are important concepts in Class 10 Science.
Activity 1.3 class10 science
Objective
To observe the chemical reaction between zinc and dilute hydrochloric acid or sulphuric
acid and identify the types of reaction involved.
Materials Required
1. Conical flask
2. Zinc granules
3. Hydrochloric acid
4. Sulphuric acid
5. Test tubes
Procedure
· Take some zinc granules in a conical flask.
· Add dilute hydrochloric acid or dilute sulphuric acid to the flask.
· Observe the reaction carefully.
· Toch the outer surface of the flask carefully and note any change in temperature.
Observation
· Bubbles of gas are produced with brisk effervescence.
· The conical flask becomes warm.
· A salt solution is formed.
Chemical Reactions
Zn + H2SO4 →ZnSO4 + H2 ↑
Zn + 2HCl →ZnCl2 + H2 ↑
Explanation
When a metal reacts with an acid, a salt and hydrogen gas are produced. This reaction
is displacement reaction. Zinc displaces hydrogen from acid and forms a salt.
During this reaction, heat also produces, so the reaction is also exothermic reaction
Types of Chemical Reactions
Displacement Reaction
A reaction in which a more reactive element displaces a less reactive from its compound is called a displacement reaction.
Exothermic reaction
A reaction in which heat is released is called an exothermic reaction.
Conclusion
The activity shows the chemical reaction between a metal and acid. The reaction is exothermic reaction and displacement reaction.
Precautions
· Perform the activity only under the supervision of a teacher.
· Handle acids carefully.
· Use clean apparatus.
· Avoid direct contact of acids with skin and eyes.
· Do not bring a flame near the reaction mixture.
Viva Questions and Answers
Q1. Which metal is used in this activity?
Answer
Zinc granules
Q2. Which gas is evolved during the reaction?
Answer
Hydrogen gas
Q3. How can hydrogen gas be identified?
Answer
Hydrogen burns with a characteristic ‘pop’ sound when a burning splint is brought near it.
Q4. Why does the flask become warm?
Answer
Because heat is released during the reaction.
Q5. Which type of reaction is demonstrated in this acidity?
Answer
Displacement reaction and exothermic reaction
Q6. What is formed when zinc reacts with sulphuric acid?
Answer
Zinc sulphate and hydrogen gas
Q7. Why is zinc able to displace hydrogen from acids?
Answer
Because zinc is more reactive than hydrogen
Key Learning Points
· Metals react with acids to produce salt and hydrogen gas.
· Zinc displaces hydrogen from dilute acids.
· Hydrogen gas is evolved during the reaction.
· Heat is released during the reaction.
· The reaction is displacement reaction.
· The reaction is also an exothermic reaction.
Multiple Choice Questions
Q1. Which metal is sed in activity 1.3?
a.Iron
b.Copper
c.Zinc
d.Silver
Correctanswer- c. Zinc
Q2.Which gas is evolved when zinc reacts with dilute acids?
a.Oxygen
b.Carbon dioxide
c.Hydrogen
d.Nitrogen
Correct answer – c. Hydrogen
Q3.What is observed during the reaction?
a.Colour change only
b.Formation of precipitate
c.Brisk effervescence and gas evolution
d.No change
Correct answer – c. Brisk effervescence and gas evolution
Q4.Why does the conical flask become warm?
a.Heat is absorbed
b.Heat is released
c.Water evaporates
d.Acid cools down
Correctanswer – b. Heat is released
Q5.Which type of reaction occurs when zinc displaces hydrogen from an acid?
a.Combination reaction
b.Decomposition reaction
c.Displacement reaction
d.Double displacement reaction
Correct answer – c. Displacement reaction
Q6.Which salt is formed when zinc reacts with sulphuric acid?
a.Zinc chloride
b.Zinc sulphate
c.Zinc oxide
d.Zinc nitrate
Correct answer – b. Zinc sulphate
Q7.The reaction between zinc and acid is also called:
a.Endothermic reaction
b.Neutralization reaction
c.Exothermic reactiond.
Photochemical reaction
Correct answer – c. Exothermic reaction
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