Which of the following compounds reacts with aqueous nitrous acid at low temperature to give an oily substance,$N$-nitrosoamine?

Which of the following has the maximum nucleophilicity?

In the given reaction sequence,$Z$ is

The electrolytic reduction of nitrobenzene in a strongly acidic medium produces:

Write short notes on the following:
$(i)$ Carbylamine reaction
$(ii)$ Diazotisation
$(iii)$ Hofmann's bromamide reaction
$(iv)$ Coupling reaction
$(v)$ Ammonolysis
$(vi)$ Acetylation
$(vii)$ Gabriel phthalimide synthesis.

Urea on slow heating gives: