Which gases are evolved when ferrous sulphate crystals are heated a SO2 and SO3 B so4 and SO3 C so4 and so?

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Observations:
Precautions:

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Ferrous sulphate crystals contain water of crystallisation (FeSO4.7H2O). On heating, ferrous sulphate crystals lose water. So their colour changes from light green to white due to the formation of anhydrous ferrous sulphate (FeSO4). When ferrous sulphate is heated, it gives ferric oxide, sulphur dioxide and sulphur trioxide.

Reaction

FeSO4 → Fe 2 O 3 + SO2 + SO3

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Procedure:

Take about 2g of ferrous sulphate crystals in a dry boiling tube and note the colour of the crystals.
Hold the boiling tube with a test tube holder and heat the boiling tube over the flame of a burner.
Smell the gas being emitted.
Observe the colour of the crystals after heating.

You can select the type of reaction form ‘Select the type of reaction’ drop down list.

Thermal Decomposition

You can select the sample form ‘Select the sample’ drop down list.
To start the experiment, click on the ‘Start’ button.
To put copper carbonate into the test tube, drag the spatula over the test tube.
To turn on the burner, click on the knob of the burner.
To heat the contents of the test tube, drag the test tube over the burner.
Wait for some time to complete the reaction.
You can see the chemical equation of the corresponding reaction on the side menu.
You can see the inference by clicking on the inference icon.
Click on the ‘Reset’ button to redo the experiment.

Electrolytic Decomposition

You can select the sample form ‘Select the sample’ drop down list.
Adjust the resistance of the rheostat using the slider.
To start/stop the experiment, click on the ‘Switch On’ button.
You can see the chemical equation of the corresponding reaction on the side menu.
You can see the inference by clicking on the inference icon.
Click on the ‘Reset’ button to redo the experiment.

Photodecomposition

You can select the sample form ‘Select the sample’ drop down list.
Use the slider to select the power of light from the source.
Use the slider to select the distance of the source from the sample.
To start/stop the experiment, click on the ‘Start’ button.
You can see the chemical equation of the corresponding reaction on the side menu.
You can see the inference by clicking on the inference icon.
Click on the ‘Reset’ button to redo the experiment.

Note: Click on the ‘HELP’ button to see the instructions.

Observations:

The ferrous sulphate crystals are light green in colour.
The gas emitted has the characteristic odour of burning sulphur.
On heating, the colour changes from light green to white.
On further heating, the white substance changes to dark brown solid.

Ferrous sulphate crystals contain water molecules (FeSO4. 7H2O). On heating, ferrous sulphate crystals lose water and anhydrous ferrous sulphate (FeSO4) is formed. So their colour changes from light green to white.
On further heating, anhydrous ferrous sulphate decomposes to form ferric oxide (Fe2O3), sulphur dioxide (SO2) and sulphur trioxide (SO3). So, the gas emitted smells like burning sulphur.

In this reaction, the single reactant FeSO4 decomposes to form three different products. So, the reaction is a decomposition reaction.

Precautions:

Do not point the mouth of the boiling tube at your neighbours or yourself.
Waft gases emitted from ferrous sulphate on heating gently towards your nose holding the test tube at a distance. The gases SO2 and SO3 are very harmful, so do not take a deep breath when smelling the odour of the gases.
Always use a test tube holder while heating the test tube.

Let’s do the experiment!

Answer

Verified

The color of ferrous sulphate crystals is green.

Ferrous sulphate crystals contain water molecules (FeSO4. 7H2O). On heating, ferrous sulphate crystals lose water and anhydrous ferrous sulphate (FeSO4) is formed. So their colour changes from light green to white.

On further heating, anhydrous ferrous sulphate decomposes to form ferric oxide (Fe2O3), sulphur dioxide (SO2) and sulphur trioxide (SO3). So, the gas emitted smells like burning sulphur.

In this reaction, the single reactant FeSO4 decomposes to form three different products. So, the reaction is a decomposition reaction.

Ahydrous ferrous Ferric oxide

Sulphate (white) (brown)