Compounds Containing Nitrogen | JEE Advanced - Free MCQ Practice Test

NOTE : Secondary amines (aliphatic as well as aromatic) react with nitrous acid to form Nnitrosoamines.

NOTE : Only primary aliphatic and aromatic amines give this test.

CHX₃ + RNH₂ + 3KOH → RNC + 3 KX + 3H₂O

TIPS/Formulae : Toluene has electron-donating methyl group. Hence reacts fastest while others have either electron withdrawing groups (i.e. – COOH or – NO₂ etc.) or no substituent.

TIPS/Formulae : Empirical Formula = n × Molecular formula
Solution : Since the molecular formula is n times the empirical formula, therefore, different compounds having the same empirical formula must have different molecular weights.

In benzylamine, electron pair on nitrogen is not delocalised due to lack of conjugation; while in all other compounds it is delocalised and hence lesser available for protonation.

TIPS/Formulae : The addition is initiated by the attack of CN^– group which is a nucleophile.

TIPS/Formulae : In the formation of cyanohydrin number of carbon atoms in parent chain increases by one.

N can't have more than 8 electrons in its valence shell as it does not have any d orbital. In (c), N has 10 electrons.

Aliphatic amines are more basic than aromatic amines because in aliphatic amines electron pair on nitrogen is not involved in resonance.

The protonated form of II would be III which is more stable because here the contributing structures (III) and (IV) are equivalent.

In   the availability of electron pair increases due to the +I effect of two CH₃ groups while in  CH₃CH₂NH₂, +I effect of only one ethyl group is operative. In  the electron availability on nitrogen decreases due to resonance as shown below

Therefore, the order of basic strength would be 1 > 3 > 2 > 4.

NOTE :  Reaction of (B) indicates that it is an aldehyde which thus should be C₂H₅CHO or CH₃CH₂CHO, hence C should be CH₃CH₂CH = NNHCONH₂

Two moles of NH₂ ions will abstract two moles of most acidic hydrogen out of the four moles of hydrogen present per mole of the acidic compound. The acidic strength is in the order:

–COOH > –OH (phenolic having NO₂ group) > –OH (phenolic) > alkynic H.

NOTE : POCl₃ is a dehydrating agent . Hence

TIPS/Formulae :– NH is an activating group where as  group is a deactivating group.
Hence electrophilic substitution will be governed by the ring having 

(i) Position (X) is most acidic due to – COOH group.
(ii) –NH₃⁺ group at position Y is more acidic than at Z because of presence of electron withdrawing – COOH group in close proximity. Hence – NH₃⁺ group at position Z is least acidic.

None of the given options is correct. Benzene sulphonic acid, being stronger acid than carbonic acid, would liberate CO₂ when treated with sodium bicarbonate, but p-nitrophenol, being less acidic than carbonic acid, will not liberate CO₂.

This is an example of carbylamine reaction

CHCl₃ + RNH₂+ KOH 

Only primary aromatic amines undergo diazotisation followed by coupling.