AIIMS 2019 Chemistry Oxides and Oxyanions MCQ Question
Assertion: is useful in purification of Zirconium (Zr)
Reason: sublimes at room temperature.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Correct Answer
Detailed Explanation
Both S₂O₇²⁻ (disulfate) and Cr₂O₇²⁻ (dichromate) do not have the same number of valence electrons; S₂O₇²⁻ has 20 valence electrons while Cr₂O₇²⁻ has 12 valence electrons from its chromium atoms and 12 from oxygen, totaling 24. Additionally, their structures differ: S₂O₇²⁻ features a central S-S bond, while Cr₂O₇²⁻ has a distinct Cr-O framework with different bonding characteristics. Therefore, option D is correct as both statements in the question are false. Options A and B are incorrect because they misrepresent the valence electron counts and structural similarities, while option C is not applicable since the information can be determined.
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