A compound of molecular formula C₈H₈O₂ reacts with acetophenone to form a single cross-aldol product in the presence of base. The same compound on reaction with conc. NaOH forms benzyl alcohol as one of the products. The structure of the compound is :

The group having triangular planar structures is :

To find the standard potential of M³⁺/M electrode,the following cell is constituted : Pt/M/M³⁺(0.001 mol L⁻¹ )/Ag⁺(0.01 mol L⁻¹ )/Ag

The emf of the cell is found to be 0.421 volt at 298 K. The standard potential of half reaction M3⁺ + 3e⁻$$ \to $$ M at 298 K will be :

(Given $$E_{A{g^ + }\,/\,Ag}^ - $$ at 298 K = 0.80 Volt)

Which one of the following is an oxide?