Question

Ferric sulphate on heating, gives
\[
  A.{\text{ }}S{O_2} \\
  B.{\text{ }}S{O_3} \\
  C.{\text{ }}S{O_3}{\text{ }}and{\text{ }}S{O_2} \\
  D.{\text{ }}none{\text{ }}of{\text{ }}the{\text{ }}above \\
 \]

Answer 1

Hint- We know the chemical formula for ferric sulphate is \[F{e_2}{(S{O_4})_3}\]. The heating of Ferric sulphate is an example of a thermal decomposition reaction.

Complete step by step answer:
We must remember ferric sulphate is a yellow crystalline salt. When we heat ferric sulphate it gets decomposes into ferric oxide \[\left( {F{e_2}{O_3}} \right)\] with the evolution of Sulphur trioxide \[(S{O_3})\]. And further decomposition of sulphur trioxide gives Sulphur dioxide \[(S{O_2})\]. So we can represents the balanced equation for this chemical reaction
\[
  F{e_2}{(S{O_4})_3} \to \left( {F{e_2}{O_3}} \right) + 3(S{O_3}) \\
  2(S{O_3}) \to 2(S{O_2}) \uparrow + {O_2} \uparrow \\
 \]
We find the product ferric oxide \[\left( {F{e_2}{O_3}} \right)\] is the one that appears on the iron products as rust during the corrosion. and It is a red color iron oxide.
Also we must remember this reaction occurs at a high-temperature requirement. Therefore it occurs at a high temperature of about 500⁰C to 700⁰C. Hence this reaction is considered as an example of a thermal decomposition reaction. This reaction also has a characteristic smell of Sulphur burning.
We can also note that the spontaneous decomposition of sulphur trioxide into sulphur dioxide along with the evolution of oxygen is also the result of high temperature in this thermal decomposition. So, the answer to the above question is both \[(S{O_3})\] and \[(S{O_2})\] which is option C.

 Note:
There is a chance to confuse ferric sulphate \[F{e_2}{(S{O_4})_3}\] with ferrous sulphate $(FeSO4)$ so we have to remember it clearly.
we should note that in both the reactions, the by-product sulphur trioxide remains the same. But, the main products change as ferric oxide and ferrous oxide respectively.