Kjeldahl's method cannot be used to estimate nitrogen for which of the following compounds?

The major product [B] in the following sequence of reactions is :-

Complexes (ML₅) of metals Ni and Fe have ideal square pyramidal and trigonal bipyramidal grometries, respectively. The sum of the 90°, 120° and 180° L-M-L angles in the two complexes is ________.

At constant volume, 4 mol of an ideal gas when heated from 300 K to 500K changes its internal energy by 5000 J. The molar heat capacity at constant volume is _______.