Identify the oxidation states of titanium ($\mathrm{Z} = 22$) and copper ($\mathrm{Z} = 29$) in their colourless compounds.

The following ion in its aqueous solution is colourless : (Atomic number: $\mathrm{Sc}=21, \mathrm{Fe}=26, \mathrm{Ti}=22, \mathrm{Mn}=25$)

The colour of light absorbed by an aqueous solution of ${\mathrm{CuSO}}_{\mathrm{4}}$ is ______.

Identify the metal that forms colourless compounds (in its $+3$oxidation state).

Select the coloured compound amongst the following.

(Atomic no. $\mathrm{Ti}=22, \mathrm{Cr}=24, \mathrm{Cu}=29, \mathrm{Zn}=30$)

Which metal is used as a part of the catalyst in the Fischer-Tropsch method?

Which of the following ion is diamagnetic?

Magnetic moment $2.84 \mathrm{B}.\mathrm{M}$. is given by ______. (At. Numbers: $\mathrm{Ni}=28, \mathrm{Ti}=22, \mathrm{Cr}=24, \mathrm{Co}=27$)

Which of the following ion has the maximum theoretical magnetic moment?