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 _______________.

Three moles of AgCl get precipitated when one mole of an octahedral co-ordination compound with empirical formula CrCl₃.3NH₃.3H₂O reacts with excess of silver nitrate. The number of chloride ions satisfying the secondary valency of the metal ion is ______________.