Complete removal of both the axial ligands (along the z-axis) from an octahedral complex leads to which of the following splitting patterns? (relative orbital energies not on scale).

5 moles of AB₂ weigh 125 × 10^–3 kg and 10 moles of A₂B₂ weigh 300 × 10^–3 kg. The molar mass of A (M_A) and molar mass of B (M_B) in kg mol are:

The increasing order of the pK_b of the following compound is :

The group number, number of valence electrons, and valency of an element with atomic number 15, respectively, are: