In the Hofmann mustard oil reaction of primary amines, the black precipitate is due to:

When aniline is nitrated with nitrating mixture in ice cold condition, the major product obtained is :

$$\displaystyle -{ NH }_{ 2 }$$ group of aniline is ortho, para directing in electrophilic substitutions.

Peroxide effect can be checked by the addition of sufficient amount of:

The major gaseous product obtained in the following reaction is:
$$CH_3-NH_2+COCl_2\rightarrow Product$$