INTRODUCTION
We will learn to determine the types of reactions happening in this experiment.
BASIC BUILDING CONCEPTS
We know that there are four types of reactions in chemistry.
1. Combination reaction,
2. Decomposition reaction,
3. Displacement reaction,
4. Double displacement reaction.
COMBINATION REACTION
In this type of reaction, two or more compounds or elements combine to form a new compound in this type of reaction. For example,
2Mg + O2 → 2MgO
Magnesium Oxygen Magnesium Oxide
The basic form of this reaction is A + X → AX
DECOMPOSITION REACTION
In this type of reaction, components or simpler compounds are formed by the breaking down of a single reactant on heating. For example,
2KClO3 → 2KCl + 3O2
Potassium Chlorate Potassium Chloride Oxygen
The basic form of this reaction is AX → A + X
DISPLACEMENT REACTION
In this type of reaction more reactive element displaces a less reactive element from its position. For example,
Zn + CuSO4 → ZnSO4 + Cu
Zinc Copper Sulphate Zinc Sulphate Copper
The basic form of this reaction is A + B X → AX + B
The Reactivity of metals depends on their capacity to lose an electron, and the reactivity of non-metals depends on their ability to gain an electron
DOUBLE DISPLACEMENT REACTION
In this type of reaction, a new compound is formed when ions of different compounds combine. For example,
NaCl + AgNO3 → NaNO3 + AgCl
Sodium Chloride Silver Nitrate Sodium Nitrate Silver Chloride
The basic form of this reaction is AX + BY → AY + BX
EXPERIMENT A
AIM
To perform the reaction between water and soda-lime and name the type of reaction it is.
MATERIAL REQUIRED
1. Calcium oxide,
2. Water,
3. Beaker,
4. Glass rode,
5. Dropper,
6. Red litmus paper,
7. Test tube,
8. Filter paper,
9. Funnel
THEORY
1. Calcium oxide and water react to form calcium hydroxide.
2. In this reaction, two compounds combine two to form a new compound. Therefore, this reaction is a combination reaction.
CaO + H2O → Ca(OH)2 + heat
Calcium Oxide Water Calcium Hydroxide
3. This reaction can also be called an exothermic reaction because heat evolved from this reaction.
PROCEDURE AND OBSERVATION TABLE
| S.NO | EXPERIMENT | OBSERVATION | INFERENCE |
|---|---|---|---|
| In a beaker, take some calcium oxide and pour water slowly into it. Stir it well using a crystal glass rod. Touch the outer surface. | With a hissing sound, a new substance will form. The outer surface is hot. | When water reacts with quicklime, a new substance is formed. Heat is evolved in this reaction. | |
| With the help of a dropper, drop this solution on litmus paper. | Red litmus changes to blue litmus. | The new substance formed is basic in nature. | |
| Filter this solution with the help of a funnel and take 5ml of this solution in a beaker. Blow air through this solution. | Carbon dioxide turns milky while passing it through clear filtrate. | The new substance formed is calcium hydroxide. |
RESULT
In this reaction, two compounds, quick lime and water, combine to form a new compound; therefore, this reaction is a combination reaction.
PRECAUTIONS
1. Handle quicklime with utmost care as it can burn severely.
2. Water must be poured slowly.
3. The Filtrate must be clean.
EXPERIMENT B
AIM
To perform the action of heat on ferrous sulphate and determine the name of this reaction.
MATERIAL REQUIRED
1. Ferrous sulphate crystals,
2. Test tubes,
3. Test tube holder,
4. Blue litmus paper.
THEORY
1. When ferrous sulphate is heated, it undergoes a decomposition reaction.
2. Ferrous sulphate is green in colour.
2FeSO4 → Fe2O3 + SO2 + SO3
Ferrous Sulphate Ferric Oxide Sulphur Dioxide Sulphur Trioxide
3. Sulphur dioxide and sulphur trioxide are acidic in nature and turn blue litmus to red.
PROCEDURE AND OBSERVATION
| S.NO | PROCEDURE | OBSERVATION | INFERENCE |
|---|---|---|---|
| In a dry test tube, take two grams of dry ferrous sulphate and note down its colour. | The ferrous sulphate crystals are green in colour. | The ferrous sulphate crystals are green in colour. | |
| Heat this test tube. | The colour changes to brown, and a colourless gas with a burning smell of sulphur is evolved. | New compounds are formed by the heating of ferrous sulphate. | |
| Bring a moist blue litmus paper in contact with gas evolved from the reaction. | Litmus paper turns red. | The nature of gas evolved is acidic. | |
| Dip a strip of litmus paper in an acidified solution of potassium chromate and bring it in contact with the evolved gas. | The orange colour of the strip turns into a green colour. | Sulphur dioxide and sulphur trioxide gases are evolved. |
RESULT
Ferric oxide, sulphur dioxide and sulphur trioxide are formed by heating ferrous sulphate. Therefore this reaction is a decomposition reaction.
PRECAUTIONS
1. Keep the mouth of the test tube containing ferrous sulphate away from you while heating.
2. Wash your hands properly after the experiment.
EXPERIMENT C
AIM
To perform the reaction between iron nails and copper sulphate solution and name this reaction.
MATERIAL REQUIRED
1. Iron nails,
2. Copper sulphate solution,
3. Test tubes,
4. Test tube stand,
5. Sandpaper
6. Thread.
THEORY
When iron nails are immersed in copper sulphate solution, iron displaces copper from its position. Therefore this reaction is a displacement reaction.
Fe + CuSO4 → Fe2SO4 + Cu
Iron Copper Sulphate Iron Sulphate Copper
Iron is more reactive than copper; therefore, it displaces copper from its position.
PROCEDURE
Step 1: With the help of sandpaper, clean two iron nails.
Step 2: Take two test tubes and pour 10 ml of copper sulphate solution into each test tube.
Step 3: Name these test tubes as A and B.
Step 4: Take one nail and tie it with a thread and immerse it in test tube A. Leave it for 20 minutes
Step 5: Take out the iron nail from the test tube and compare the intensity of the colour of both the test tubes.
Step 6: Compare the intensity of the colour of the iron nail also.
OBSERVATION
1. The colour of the copper sulphate solution was blue, which changed into light green after immersing an iron nail in it.
2. The colour of the iron nail was grey which changed to reddish-brown colour after immersing it in copper sulphate solution.
RESULT
Iron displaces copper from its position because iron is more reactive than copper. In this reaction, two products are formed, which are copper and ferrous sulphate. This reaction is a displacement reaction.
PRECAUTION
1. Iron nails must be cleaned to immerse them in copper sulphate solution.
2. Do not disturb the test tube, which contains iron nails and copper sulphate solution.
EXPERIMENT D
AIM
To perform the reaction between sodium sulphate and barium chloride and name this reaction.
MATERIAL REQUIRED
1. Sodium sulphate solution,
2. Barium chloride solution,
3. Test tube,
4. Beaker.
THEORY
When sodium sulphate solution and barium chloride are mixed together, a white precipitate of barium sulphate is formed.
Na2SO4 + BACl2 → BaSO4 + 2NaCl
Sodium Sulphate Barium Chloride Barium Sulphate Sodium Chloride
The type of this reaction is called the double displacement reaction.
PROCEDURE
Step 1: In a test tube, take 5ml of sodium sulphate and name it as A.
Step 2: Take 5ml barium chloride and name it as B in another test tube.
Step 3: Mix these solutions in a beaker.
Step 4: Stir that mixture with the help of a glass rod.
Step 5: Note down your observation.
OBSERVATION
A white precipitate is formed by mixing sodium sulphate and barium chloride.
RESULT
1. A double displacement reaction will occur in this reaction.
2. Barium sulphate and sodium chloride are formed by mixing sodium sulphate and barium chloride.
PRECAUTIONS
1. Every piece of equipment should be cleaned before use.
2. Use an equal volume of sodium sulphate and barium chloride.
Viva Questions and Answers
Q.1 What do you mean by displacement reaction?
ANS. In this type of reaction more reactive element displaces a less reactive element from its position.
Q.2 Give an equation of the reaction between zinc and copper sulphate?
ANS. Zn + CuSO4 → ZnSO4 + Cu
Zinc Copper Sulphate Zinc Sulphate Copper
Q.3 What do you mean by decomposition reaction?
ANS. In this type of reaction, components or simpler compounds are formed by the breaking down of a single reactant on heating.
Q.4 What do you mean by double displacement reaction?
ANS. In this type of reaction, a new compound is formed when ions of different compounds combine.
Q.5 What do you mean by composition reaction?
ANS. In this type of reaction, two or more compounds or elements combine together to form a new compound.
Q.6 Give an equation for the reaction between sodium sulphate and barium chloride?
ANS. Na2SO4 + BACl2 → BaSO4 + 2NaCl
Sodium Sulphate Barium Chloride Barium Sulphate Sodium Chloride
Q.7 What kind of reaction is this/
ANS. Double displacement reaction.
Q.8 What was the aim of our experiment?
ANS. To perform different reactions and determine their type.
Q.9 Give an equation of the reaction between iron and copper sulphate solution?
ANS. Fe + CuSO4 → Fe2SO4 + Cu
Iron Copper Sulphate Iron Sulphate Copper
Q.10 Name the kinds of chemical reactions?
ANS. Chemical reactions are of four types;
1. Composition reaction,
2. Displacement react,
3. Double displacement reaction,
4. Composition reaction.
Saquib Siddiqui is a Mechanical Engineer and a content creator. He has special interest in science experiments and teaches the same to school and college students. He is also a technical lead at RUDE LABS PVT. LTD.
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