Question

Ferrous sulphate decomposes with the evolution of a gas having a characteristic odour of burning sulphur. Write the chemical
reaction involved and identify the type of reaction.

NCERT Class X
Science - Exemplar Problems

Chapter_Chemical Reactions And Equations

Answer 1

2FeSO4=Fe2O3+SO2+SO3  IT IS DECOPOSITION REACTION.

Answer 2

The decomposition of ferrous sulphate on heating forms ferric oxide, Sulphur dioxide gas and Sulphur trioxide gas. The burning sulphur smell is due to presence of these two gases.

The reaction is given below:

$\bold{2 \mathrm{FeSO}_{4}(\mathrm{s})+\mathrm{Heat} \rightarrow \mathrm{Fe}_{2} \mathrm{O}_{3}(\mathrm{s})+\mathrm{SO}_{2}(\mathrm{g})+\mathrm{SO}_{3}(\mathrm{g})}$

Since, in this reaction, molecules of ferrous sulphate decomposes on heating, hence, this type of reactions are called as thermal decomposition reactions.  Decomposition term indicates the breaking of molecule into more than one products. This reaction is also a redox reaction.