The catalytic activity of transition metals and their compounds is ascribed mainly to

Four successive members of the first series of the transition metals are listed below. For which one of them the standard potential $$\left( {E_{{M^{2 + }}/M}^o} \right)$$ value has a positive sign?

Which one of the following does not correctly represent the correct order of the property indicated against it?

In which of the following arrangements the given sequence is not strictly according to the property indicated against it?