Which of the following represents a pair of enantiomers?

Which of the following does not show optical isomerism?

$[PtCl_2(en)_2]$ possesses which type of isomerism?

Which of the following complex species is not expected to exhibit optical isomerism?

Two soluble salts of iron $A$ & $B$,on combining with excess of a reagent $(R)$ produce compound $C$ (pale yellow) & $D$ (yellow) respectively. Reaction of $A$ with $D$ and that of $B$ with $C$ both produce a blue coloured compound. Which of the following statements is correct?

What is the value of the magnetic moment of $Co^{2+}$ (in $BM$)?