Which salt from following forms aqueous solution having $$\mathrm{pH}$$ less than 7 ?

Identify neutral ligand from following

Identify the product 'B' in following reaction.

Ethyl phenyl ketone $$\mathrm{\buildrel {{H_2}N - N{H_2}} \over \longrightarrow}$$ A $$\mathrm{\mathrel{\mathop{\kern0pt\longrightarrow} \limits_\Delta ^{KOH,HO - {{(C{H_2})}_2} - OH}}}$$

Which of the following amines undergoes acylation reaction?