Q25 / 160 · TS EAMCET 2008 · Chemistry

Which one of the following reactions does not occur?

  • A
    $\mathrm{F}_2+2 \mathrm{Cl}^{-} \longrightarrow 2 \mathrm{~F}^{-}+\mathrm{Cl}_2$
  • Correct answer
    B
    $\mathrm{Cl}_2+2 \mathrm{~F}^{-} \longrightarrow 2 \mathrm{Cl}^{-}+\mathrm{F}_2$
  • C
    $\mathrm{Br}_2+2 \mathrm{I}^{-} \longrightarrow 2 \mathrm{Br}^{-}+\mathrm{I}_2$
  • D
    $\mathrm{Cl}_2+2 \mathrm{Br}^{-} \longrightarrow 2 \mathrm{Cl}^{-}+\mathrm{Br}_2$

Solution

With progressive increase in atomic number, the reduction potential of halogens decreases, thus oxidising power also decreases. Hence, a halogen with lower atomic number will oxidise the halide ion of higher atomic number and therefore, will liberate them from their salt solution. Hence, the reaction $$ \mathrm{Cl}_2+2 \mathrm{~F}^{-} \longrightarrow 2 \mathrm{Cl}^{-}+\mathrm{F}_2 $$ is not possible.

Hence, the correct answer is option: 'B'.

Relevant Questions