Given below are two statements: Statement I: The number of pairs among [ Ti ^ 4+ , V ^ 2+ ], [ V ^ 2+ , Mn ^ 2+ ], [ Mn ^ 2+ , Fe ^ 3+ ] and [ V ^ 2+ , Cr ^ 2+ ] in which both ions are coloured is 3. Statement II: The number of pairs among [ La ^ 3+ , Yb ^ 2+ ], [ Lu ^ 3+ , Ce ^ 4+ ] and [ Ac ^ 3+ , Lr ^ 3+ ] ions in which both are diamagnetic is 3. In the light of the above statements, choose the correct from the options given below:
A. Both Statement I and Statement II are correct
For Statement I: The electronic configurations of the given transition metal ions are: Ti ^ 4+ : 3d^0 (colourless due to absence of unpaired electrons) V ^ 2+ : 3d^3 (coloured) Mn ^ 2+ : 3d^5 (coloured) Fe ^ 3+ : 3d^5 (coloured) Cr ^ 2+ : 3d^4 (coloured) The pairs in which both ions are coloured are [ V ^ 2+ , Mn ^ 2+ ], [ Mn ^ 2+ , Fe ^ 3+ ], and [ V ^ 2+ , Cr ^ 2+ ]. The pair [ Ti ^ 4+ , V ^ 2+ ] contains Ti ^ 4+ which is colourless. Thus, there are exactly 3 pairs where both ions are coloured. Statement I is correct. For Statement II: The electronic configurations of the given f-block ions are: La ^ 3+ : [ Xe ] 4f^0 (diamagnetic) Yb ^ 2+ : [ Xe ] 4f^ 14 (diamagnetic) Lu ^ 3+ : [ Xe ] 4f^ 14 (diamagnetic) Ce ^ 4+ : [ Xe ] 4f^0 (diamagnetic) Ac ^ 3+ : [ Rn ] 5f^0 (diamagnetic) Lr ^ 3+ : [ Rn ] 5f^ 14 (diamagnetic) All the given ions have either an f^0 or f^ 14 configuration, meaning they have no unpaired electrons and are diamagnetic. Therefore, in all 3 pairs, both ions are diamagnetic. Statement II is correct. Both Statement I and Statement II are correct. Answer: Both Statement I and Statement II are correct
Related: Chemistry — d and f Block Elements · All PYQ Banks