Which of the following reagents reacts with ammonia to form a brown precipitate?

Primary and secondary amines are distinguished by

$A$ positive carbylamine test is given by :-
$(a)$ $N,N$-Dimethylaniline
$(b)$ $2,4$-Dimethylaniline
$(c)$ $N$-methyl-$o$-methylaniline
$(d)$ $p$-Methylbenzylamine

$p-$chloroaniline and anilinium hydrochloride can be distinguished by

Which of the following gives $RNC$ when reacted with $CHCl_3$ and $KOH$?

Which of the following substances does not give the iodoform test?