Question

Complete the following statements by choosing the correct type of reaction for x and y.

Statement 1. The heating of ammonium dichromate is an example of ‘x’ reaction

Statement 2. The heating of zinc oxide with coke is an example of ‘y’ reaction.

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The correct option is D

The explanation for the correct option

Option (D)

Heating of ammonium dichromate

On heating ammonium dichromate $\left({\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7\right)$, dichromate decomposes into nitrogen $\left({\mathrm{N}}_2\right)$, water ${\mathrm{H}}_2\mathrm{O}$ and chromium oxide $\left({\mathrm{Cr}}_2{\mathrm{O}}_3\right)$.

${\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7\left(\mathrm{s}\right)\stackrel{∆}{\to }{\mathrm{N}}_2\left(\mathrm{s}\right)+4{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)+{\mathrm{Cr}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)$

Hence, heating of ammonium dichromate is an example of a ‘decomposition’ reaction.

Heating of zinc oxide with coke

By heating zinc oxide $\left(\mathrm{ZnO}\right)$ and coke $\left(\mathrm{C}\right)$ together we get zinc $\left(\mathrm{Zn}\right)$ and carbon monoxide $\left(\mathrm{CO}\right)$.

$\mathrm{ZnO}\left(\mathrm{s}\right)+\mathrm{C}\left(\mathrm{s}\right)\stackrel{∆}{\to }\mathrm{Zn}\left(\mathrm{s}\right)+\mathrm{CO}\left(\mathrm{g}\right)$

Here, zinc gets reduced and carbon gets oxidized.

Hence, the heating of zinc oxide with coke is an example of a 'redox' reaction.

Therefore, ‘x’ means ‘decomposition’ and ‘y’ means ‘redox’.