In following pairs, the one in which both transition metal ions are colourless is :

In neutral or faintly alkaline medium, $$\mathrm{KMnO}_{4}$$ being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be :

Which among the following is the strongest Bronsted base?

Which among the following pairs of the structures will give different products on ozonolysis? (Consider the double bonds in the structures are rigid and not delocalized.)