Question

Identify the decomposition reaction from the following options:

• A. $\mathrm{Fe}\left(s\right)+{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)\to {\mathrm{FeSO}}_4\left(\mathrm{aq}\right)+\mathrm{Cu}\left(s\right)$
• B. ${\mathrm{FeSO}}_4\left(\mathrm{aq}\right)+\mathrm{Zn}\left(s\right)\to {\mathrm{ZnSO}}_4\left(\mathrm{aq}\right)+\mathrm{Fe}\left(s\right)$
• C. $2\mathrm{CO}\left(g\right)+O_2\left(g\right)\to 2{\mathrm{CO}}_2\left(g\right)$
• D. $2{\mathrm{FeSO}}_4\left(s\right)\to {\mathrm{Fe}}_2{O}_3\left(s\right)+{\mathrm{SO}}_2\left(g\right)+{\mathrm{SO}}_3\left(g\right)$

Answer 1

The correct option is D $2{\mathrm{FeSO}}_4\left(s\right)\to {\mathrm{Fe}}_2{O}_3\left(s\right)+{\mathrm{SO}}_2\left(g\right)+{\mathrm{SO}}_3\left(g\right)$

In a decomposition reaction, a single reactant breaks down into multiple products.

Reaction	No. of product(s)	No. of reactant(s)
$\mathrm{Fe}\left(s\right)+{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)\to {\mathrm{FeSO}}_4\left(\mathrm{aq}\right)+\mathrm{Cu}\left(s\right)$	2	2
${\mathrm{FeSO}}_4\left(\mathrm{aq}\right)+\mathrm{Zn}\left(s\right)\to {\mathrm{ZnSO}}_4\left(\mathrm{aq}\right)+\mathrm{Fe}\left(s\right)$	2	2
$2\mathrm{CO}\left(g\right)+O_2\left(g\right)\to 2{\mathrm{CO}}_2\left(g\right)$	1	2
$2{\mathrm{FeSO}}_4\left(s\right)\to {\mathrm{Fe}}_2{O}_3\left(s\right)+{\mathrm{SO}}_2\left(g\right)+{\mathrm{SO}}_3\left(g\right)$	3	1

Single reactant ⇒ Decomposition, i.e., $2{\mathrm{FeSO}}_4\left(s\right)\to {\mathrm{Fe}}_2{O}_3\left(s\right)+{\mathrm{SO}}_2\left(g\right)+{\mathrm{SO}}_3\left(g\right)$