The magnetic moment of a transition metal ion is $\sqrt{15} \ \text{BM}$. Therefore,the number of unpaired electrons present in it,is:

The species that can have a $trans$-isomer is: ($en = \text{ethane-}1,2\text{-diamine}$,$ox = \text{oxalate}$)

The two compounds pentaamminesulphatocobalt $(III)$ bromide and pentaamminesulphatocobalt $(III)$ chloride represent:

Which of the following complex ions exhibits geometrical isomerism?

Which complex is likely to show optical activity?

The $d-$ electron configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+}$ and $Co^{2+}$ are $d^4, d^5, d^6$ and $d^7$ respectively. Which one of the following will exhibit the lowest paramagnetic behaviour? (Atomic no. $Cr = 24, Mn = 25, Fe = 26, Co = 27$).