Q87 / 180 · AIIMS 2005 · Chemistry

Assertion : Borax bead test is not suitable for $\mathrm{Al}(\mathrm{III})$. Reason : $\mathrm{Al}_2 \mathrm{O}_3$ is insoluble in water.

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

Solution

Borax bead test is not suitable for $\mathrm{Al}$ (III) because its oxidising as well as reducing flame is colourless in both hot as well as cold. Alumina is insoluble in water as they exist in hydrated form like $\mathrm{Al}_2 \mathrm{O}_3 \cdot 2 \mathrm{H}_2 \mathrm{O}, \mathrm{Al}_2 \mathrm{O}_3 \cdot \mathrm{H}_2 \mathrm{O}$ etc.

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

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