Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
Answer
(1) Both Statement I and Statement II are correct
Solution
Statement I: an ion is coloured when it has unpaired d electrons (d–d transition).
Ti4+ (3d0) is colourless, while V2+ (3d3) is violet, Mn2+ (3d5) pink, Fe3+ (3d5) yellow and Cr2+ (3d4) blue.
So both ions are coloured in [V2+, Mn2+], [Mn2+, Fe3+] and [V2+, Cr2+], i.e. 3 pairs, and Statement I is correct.
Statement II: La3+ (4f0), Yb2+ ( 4f14), Lu3+ ( 4f14), Ce4+ (4f0), Ac3+ (5f0) and Lr3+ ( 5f14) have no unpaired electron, so all are diamagnetic and all 3 pairs qualify; hence Statement II is correct.
Answer: (1)