Among Co , Ti , V and Cr ions, one if used as a reagent cannot liberate H from dilute mineral acid s — d and f Block Elements Chemistry Question

Question

Among Co , Ti , V and Cr ions, one if used as a reagent cannot liberate H from dilute mineral acid solution, its spin-only magnetic moment in gaseous state is ……B.M. (Nearest integer) 3+ 2+ 2+ 2+ 2