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Question
Give reasons: Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured.
Solution 1
Sc3+ has no unpaired electron. So, it is colourless, whereas Ti3+ has one unpaired electron. Hence, it is coloured
Solution 2
Compounds of transition elements are coloured due to the presence of unpaired electrons in d-orbitals as they show d-d-transition. In Sc+3 there are no d-electrons in Ti+3 there is one d-electrons.
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