$Fac$ and $Mer$ isomerism is associated with which of the following general formula?

Which of the following complexes shows ionization isomerism?

The two compounds $[Co(SO_4)(NH_3)_5]Br$ and $[Co(SO_4)(NH_3)_5]Cl$ represent:

What type of color is observed when a compound absorbs $red$ coloured light?

Which of the following complexes exhibits both geometric and optical isomerism?

Identify the metal ions among $Co^{2+}, Ni^{2+}, Fe^{2+}, V^{3+}$ and $Ti^{2+}$ having a spin-only magnetic moment value more than $3.0 \ BM$. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is . . . . . . .