The correct order of following 3d metal oxides, according to their oxidation numbers is :

(a) CrO₃, (b) Fe₂O₃, (c) MnO₂, (d) V₂O₅, (e) Cu₂O

Which one of the following compounds will liberate CO₂, when treated with NaHCO₃ ?

An organic compound 'A' C₄H₈ on treatment with KMnO₄/H⁺ yields compound 'B' C₃H₆O.

Compound 'A' also yields compound 'B' an ozonolysis. Compound 'A' is :

The number of sigma bonds in


is _______________.