Experiment # 1
Types of Reactions - Combination, Decomposition, Displacement, Double
displacement
Aim: Performing and observing the actions of-
1. Water on Quicklime
2. Heat on ferrous sulphate crystals
3. Iron nails dipped in copper sulphate solution
4. The reaction between sodium sulphate and barium chloride solution
On the following reactions-
1. Combination reaction
2. Decomposition reaction
3. Displacement reaction
4. Double displacement reaction
A. Combination
Materials Required
1. Quick lime (Calcium oxide)
2. Borosil beaker
3. Glass rod
4. Distilled water
5. Dropper
6. Test tube
7. Litmus paper strips
Procedure
1. Wash a borosil beaker with distilled water and dry it.
2. Take a small amount of calcium oxide (quick lime) and slowly add water to it.
3. Wash and take a clean glass rod to stir the mixture of quick lime and water.
4. Touch the beaker carefully from outside.
5. Observe the change.
6. With the help of dropper take a few drops of the mixture from the beaker and place it
on red and blue litmus paper strips.
7. Wait and observe.
Observation
Experiment Observation
Mixture in A hissing sound is heard during the reaction when water is added to the
beaker beaker containing quick lime. Due to the evolution of heat during the
reaction the temperature increases and makes the solution hot.
Solution on Drops on the red litmus paper strip change the colour of the paper to blue
litmus whereas there is no colour change observed on the blue litmus paper.
paper
Result and Conclusion
From the above experiment, we can conclude that the reaction that occurred between
calcium oxide (Quick lime) and water combined to produce one single product slaked lime
(Ca(OH)2) is called a combination reaction as well as an exothermic reaction.
Precautions to be taken during the Experiment
● Take a small amount of compound such as quick lime to perform the experiment.
● Since the reaction is exothermic avoid touching the mixture directly.
● Carefully pour water into the borosil beaker containing calcium oxide (quick lime).
● Calcium oxide causes severe burns and therefore it should be handled with a
spatula.
● Use a good quality glass beaker during the experiment because if the beaker is of
poor quality then there are chances of cracking on the beaker due to the exothermic
reaction.
B. Decomposition
Materials Required
1. Ferrous sulphate crystals
2. Test tube holder
3. Boiling tube
4. Bunsen burner
5. Safety glass
6. Litmus paper strips
Procedure
1. Wash a boiling tube with distilled water and dry it.
2. Take 2 grams of ferrous sulphate crystals in the tube.
3. Make a note of the colour of the crystals.
4. Use a test tube holder to hold the boiling tube.
5. Heat the boiling tube on the bunsen burner as shown in the figure.
6. Observe the colour of the residue got and smell the odour of the gases evolved.
7. Tiny colourless water droplets are seen near the neck of the tube.
8. Gently turn it towards your nose and smell for any gas evolved.
9. Wet blue and red litmus paper strips.
10. Hold the litmus paper strips near the mouth of the boiling tube.
11. Observe the change
12. Classify the type of reaction.
Observation
Experiment Observation
Boiling tube ● Colour of Ferrous sulphate crystals changes from green to white
test and later brown.
● The gas evolved smells like burning sulphur.
Litmus paper ● Blue litmus paper strip turns red when comes in contact with gas.
test
Result and Conclusion
From the above experiment, we can conclude that the reaction occurred on heating ferrous
sulphate crystals is decomposition reaction which decomposes to produce Fe2O3, SO2, and
SO3. Since this decomposition reaction is carried out by heating it is also known as a
thermal decomposition reaction.
Precautions to be taken during the Experiment
● Do not keep the mouth of the boiling tube towards yourself.
● Do not smell the gas by directly getting it under your nose but gently turn it towards
your nose and blow it with your hand.
● Wearing safety glasses is important while you are performing this experiment.
● Thoroughly wash the boiling tube with distilled water and dry it before using it.
● Use good quality boiling tube while heating the ferrous sulphate crystals.
● Take care to keep the sulphur dioxide and sulphur trioxide gas coming in contact with
your eyes as they cause irritation to eyes.
C. Displacement
Materials Required
1. Test tube stand
2. Two test tubes
3. Two iron nails
4. Measuring cylinder
5. Beaker
6. Sandpaper
7. Copper sulphate solution
8. Laboratory stand with clamp
9. Distilled water
10. Thread
Procedure
1. Wash two test tubes with distilled water and dry them.
2. Label the test tube as P and Q.
3. Add 20mL of distilled water in the test tube and mix copper sulphate crystals in P.
4. Transfer 10Ml of solution from P to Q.
5. Take two iron nails by cleaning them with sandpaper.
6. Take one iron nail and dip it in the CuSO4 in test tube P for 15 minutes.
7. Take another iron nail and dip it in the CuSO4 in test tube Q for 15 minutes.
8. Observe the intensity of the blue colour of CuSO4 before and after the experiment
performed in test tube P and Q.
9. Record your results.
Observation
Experiment Before Experiment After Experiment
Colour of CuSo4 Blue Green
Colour of iron nail Silvery grey Brownish red coating
Result and Conclusion
From the above experiment, we can conclude that the reaction occurred when iron nails
were dipped in the copper sulphate solution for 15 minutes the colour of the solution
changes to green and brownish red copper metal is deposited on the nail. Therefore this is a
displacement reaction.
Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)
Precautions to be taken during the Experiment
● Clean the iron nails by sandpaper before dipping them in a copper sulphate solution.
● Make dilute CuSO4 for the experiment otherwise, the colour change will not be seen
in its concentrated form.
● Use good quality boiling tube.
D. Double Displacement
Materials Required
1. Test tube stand
2. Measuring cylinder
3. Two test tubes
4. Glass rod
5. Conical flask
6. Barium chloride solution
7. Sodium sulphate solution
Procedure
1. Take two test tubes, wash them with distilled water and dry them.
2. Label the test tube as P and Q.
3. Pour 5mL of barium chloride in the test tube P and observe the colour.
4. Pour 5mL of sodium sulphate in the test tube Q and observe the colour.
5. Take a conical flask and pour the solutions from both the test tube into it.
6. Stir the mixture added to the conical flask with a glass rod.
7. Keep it undisturbed for some time.
8. Observe the change in colour of the solution.
9. Record your results in the below-given table.
Observation
Experiment Observation
Colour of test tube P and test tube Q Colourless
Mixture of solution in conical flask Precipitation is formed
Result and Conclusion
From the above experiment, we can conclude that the reaction occurred on mixing the
solutions of barium chloride and sodium sulphate produce a white precipitate compound by
exchanging their ions. This reaction is known as a double displacement reaction.
Precautions to be taken during the Experiment
● The test tube, glass rod, and conical flask should be washed with distilled water and
dried before the experiment.
● The volume of sodium sulphate and barium chloride should be equal.
● Do not try to taste or touch the chemicals.
● While combining the solutions in the mixture pour sodium sulphate first and then
slowly add barium chloride to it.
