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Question
Give reason for the following statement:
[Ti(H2O)]3+ is coloured while [Sc(H2O)6]3+ is colourless.
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Solution
[Ti(H2O)]3+ is coloured because Ti3+(3d1) has one unpaired electron which undergoes a d-d transition so it is coloured. While [Sc(H2O)6]3+ (3d0) has no unpaired electrons so it will not undergo d-d transition so it is colourless.
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