Q76 / 180 · AIIMS 2019 (26 May) · Chemistry

Assertion : $\mathrm{ZrI}_4$ is useful in purification of zirconium (Zr). Reason : $\mathrm{ZrI}_4$ sublimise at room temperature.

  • A
    If both assertion and reason are true and reason is the correct explanation of assertion.
  • B
    If both assertion and reason are true but reason is not the correct explanation of assertion.
  • Correct answer
    C
    If assertion is true but reason is false.
  • D
    If both assertion and reason are false.

Solution

van-Arkel process $\underset{\text { (Impure) }}{\mathrm{Zr}+2 \mathrm{I}_2} \stackrel{870 \mathrm{~K}}{\longrightarrow} \mathrm{ZrI}_4 \underset{\substack{\text { Tungsten } \\ \text { filament }}}{\frac{1800 \mathrm{~K}}{\longrightarrow}} \underset{\text { (Pure) }}{\mathrm{Zr}+2 \mathrm{I}_2}$ $\mathrm{ZrI}_4$ is a covalent volatile substance which gets decomposed by heating over a tungsten filament at $1800 \mathrm{~K}$ to give pure $\mathrm{Zr}$.

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

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