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# Following Are the Transition Metal Ions of 3d Series:Which Ion is Most Stable in an Aqueous Solution and Why?Which Ion is a Strong Oxidising Agent and Why?Which Ion is Colourless and Why? - Chemistry

#### Question

Following are the transition metal ions of 3d series:

Ti4+, V2+, Mn3+, Cr3+

(Atomic numbers: Ti = 22, V = 23, Mn = 25, Cr = 24)

1) Which ion is most stable in an aqueous solution and why?

2) Which ion is a strong oxidising agent and why?

3) Which ion is colourless and why?

#### Solution

1)

 Gaseous ions Number of unpaired electrons Ti4+, [Ar] 3d0 0 V2+, [Ar] 3d3 3 Mn3+, [Ar] 3d4 4 Cr3+, [Ar] 3d3 3

V2+ and Cr3+ are the most stable ions in aqueous solutions owing to t_(2g)^3 a configuration.

2) An examination of the Eo values for the redox couple M3+/M2+ (from electrode potential table) shows that Mn3+ ion are the strongest oxidising agents in aqueous solutions.

3) Only the ions that have electrons in d-orbital and in which d-d transition is possible will be coloured. The ions in which d-orbitals are empty or completely filled will be colourless as no d-d transition is possible in those configurations.
From the given transition metal ions, it can be easily observed that only Ti4+ has an empty d-orbital, so, it is colourless ion.

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