Test: MCQs (One or More Correct Option): Compounds Containing Nitrogen | JEE Advanced - JEE MCQ

TIPS/Formulae : Silver nitrite, being a salt of nitrous acid, occurs in two tautomeric forms.

 ion from AgNO₂ may exist in two tautomeric forms, –O – N = O (nitrite ion) forming alkyl nitrites, and   (nitro group) forming nitroalkanes.

2 C₂H₅Br + 2AgNO₂ → C₂H₅NO₂ + C₂H₅ONO + 2 AgBr

This is an example of Hoffmann degradation of amides.

TIPS/Formulae : Nitro group decreases the electron density at the meta-position in comparison to ortho and para position due to –I and –M effects.

The above intermediate is a resonance hybrid of three structures, hence is more stable than the corresponding intermediate from ortho and paraattack

In I^st structure N has complete octet , whereas in II^nd structure N has 10e in its valence shell.
Because of 1 double and 3 single bonds of N.

TIPS/Formulae : Anilinium hydrochloride has ionisable chlorine whereas chlorobenze has non ionizable chlorine. Thus anilium hydrochloride gives white precipitate of AgCl with AgNO₃.

In chloroaniline, –Cl is directly attached to benzene ring, hence it is non-reactive.

NOTE : Only primary amines give carbylamine test.
Hence 2,4-dimethylanilinc and p-methyl–benzylamine both give this test.

Lower amines like NH₃, CH₃NH₂ and (CH₃)₂NH break diborane molecule unsymmetrically, while larger amines like (CH₃)₃N, C₅H₅N break diborane in symmetrical manner.

In ice, water molecules are excessively H-bonded giving a cage-like structure which is lighter than water.
Primary amines are more basic than tertiary amine, because the protonated 1° amines are extensively H-bonded and hence more stable than the corresponding protonated 3° amines.

Acetic acid undergoes dimerisation in benzene.

group is acetylated by acetic anhydride in methylene chloride (solvent). Note that —CONH₂ group does not undergo acetylation because here lone pair of electrons is delocalised.