The final major product of the following reaction is :

The variation of molar conductivity with concentration of an electrolyte (X) in aqueous solution is shown in the given figure.
The electrolyte X is :

The rate constant (k) of a reaction is measured at differenct temperatures (T), and the data are plotted in the given figure. The activation energy of the reaction in kJ mol^–1 is :
(R is gas constant)

The compound that has the largest H–M–H bond angle (M = N, O, S, C) is :