Which of the following forms a colourless solution in aqueous medium?

Which of the following triads has approximately equal size?

Which of the following compounds is expected to be coloured?

Which $d-$block element is expected to have the highest enthalpy of atomisation among the following?

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

Which of the following ions exhibit the same value of spin-only magnetic moment? $(A)$ $Ti^{3+}$, $(B)$ $Cr^{3+}$, $(C)$ $Mn^{2+}$, $(D)$ $Fe^{3+}$, $(E)$ $Sc^{3+}$. Choose the most appropriate answer from the options given below.