The aqueous solution containing which one of the following ions will be colourless?

Which of the following statements is incorrect?

Given below are two statements:
Statement $I$: $Cr^{2+}$ is oxidising and $Mn^{3+}$ is reducing in nature.
Statement $II$: $Sc^{3+}$ compounds are repelled by the applied magnetic field.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following pairs does not consist of isoelectronic species? (Atomic numbers: $Sm = 62, Er = 68, Yb = 70, Lu = 71, Eu = 63, Tb = 65, Tm = 69$)

The maximum oxidation state of $Cr$ is:

The first transition element is