The (major) product $(A)$ is:

In the following reactions,the major product $W$ is

Which alkene is obtained as the major product in the given reaction?

Which gas will be evolved out when $[CH_3CH_2NH_2 + (CH_3)_2CHNH_2]$ is treated with sodium nitrite and $HCl$?

Account for the following:
$(i)$ $pK_{b}$ of aniline is more than that of methylamine.
$(ii)$ Ethylamine is soluble in water whereas aniline is not.
$(iii)$ Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
$(iv)$ Although amino group is $o-$ and $p-$ directing in aromatic electrophilic substitution reactions,aniline on nitration gives a substantial amount of $m$-nitroaniline.
$(v)$ Aniline does not undergo Friedel-Crafts reaction.
$(vi)$ Diazonium salts of aromatic amines are more stable than those of aliphatic amines.
$(vii)$ Gabriel phthalimide synthesis is preferred for synthesising primary amines.

Phenyl isocyanides are prepared from which of the following reactions?