The coordination number of Th in K₄[Th(C₂O₄)₄(OH₂)₂] is :
(C₂O$${_4^{2 - }}$$ = Oxalato)

The major product of the following reaction is :

In the following compound,



the favourable site/s for protonation is/are :

A compound 'X' on treatment with Br₂/NaOH, provided C₃H₉N, which gives positive carbylamine test. Compound 'X' is :