(A) For more polarity electronegativity difference should be more E.N.(P)≈E.N.(H)N−H>As−H>Sb−H>P−H is the order,
(B) and
(C) more is the size is gaseous phase less is hydration thus less is hydrated size ∴ more is ionic mobility.
(D) Lattice energy depends on charge of cation and anion and internuclear distance thus order MgO>SrO>NaF