The strong oxidising agent is Co\(^3{+}\).
The number of unpaired electrons in Co\(^3{+}\) (\([3d^6]\)) is 4.
The spin-only magnetic moment is given by: \[ \mu = \sqrt{n(n+2)} \, \text{BM} \]
Substituting \(n = 4\):
\[ \mu = \sqrt{4(4+2)} = \sqrt{24} \approx 5 \, \text{BM} \]
The compounds of \( \text{Ti}^{4+} \) ions are colourless due to ___________.