Learn Organic Compounds Containing Nitrogen MCQ questions & answers in Organic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
11.
Which of the following can undergo electrophilic substitution when treated with nitrous acid at $${0^ \circ }C?$$
Nitrosonium $$ion,\mathop N\limits^ + O$$ from $$HONO$$ is a weak electrophile, hence it can attack only on highly activated benzene nucleus, provided proper position, $$p-$$ or $$o-$$ is free.
12.
Arrange the following amines in the order of increasing basicity.
A
B
C
D
Answer :
Aliphatic amines are more basic than aromatic amines thus methylamine is most basic. Electron donating groups increase the basicity whereas electron withdrawing groups decrease the basicity of the aromatic amines. Thus $$p$$ - methoxyaniline is more basic then aniline which is further more basic then $$p$$ - nitroaniline.
13.
The correct order of increasing basic nature for the bases $$N{H_3},C{H_3}N{H_2}\,{\text{and}}\,{\left( {C{H_3}} \right)_2}NH$$ is
A
$$\left( {C{H_3}} \right)NH < N{H_3} < C{H_3}N{H_2}$$
B
$$N{H_3} < C{H_3}N{H_2} < {\left( {C{H_3}} \right)_2}NH$$
C
$$C{H_3}N{H_2} < {\left( {C{H_3}} \right)_2}NH < N{H_3}$$
D
$$C{H_3}N{H_2} < N{H_3} < {\left( {C{H_3}} \right)_2}NH$$
The alkyl groups are electron releasing group $$\left( { + I} \right),$$ thus increases the electron density around the nitrogen thereby increasing the availability of the lone pair of electrons to proton or lewis acid and making the amine more basic. Hence more the no. of alkyl group more basic is the amine. Therefore the correct order is $$N{H_3} < C{H_3}N{H_2} < {\left( {C{H_3}} \right)_2}N$$
14.
Primary nitro compounds react with nitrous acid to form nitrolic acids which dissolve in $$NaOH$$ giving
A
yellow solution
B
blue solution
C
colourless solution
D
red solution
Answer :
red solution
Red solution
15.
Which one of the following methods is neither meant for the synthesis nor for separation of amines?
A
Curtius reaction
B
Wurtz reaction
C
Hofmann method
D
Hinsberg method
Answer :
Wurtz reaction
Wurtz reaction is for the preparation of hydrocarbons from alkyl halide $$RX + 2Na + XR \to R - R + 2NaX$$
16.
When aniline reacts with oil of bitter almonds $$\left( {{C_6}{H_5}CHO} \right)$$ condensation takes place and benzal derivative is formed. This is known as
A
Million's base
B
Schiff's reagent
C
Schiff's base
D
Benedict's reagent
Answer :
Schiff's base
Benzaldehyde reacts with primary aromatic amine to form schiff's base
\[\underset{\text{Benzaldehyde}}{\mathop{{{C}_{6}}{{H}_{5}}CH}}\,=O+\underset{\text{Aniline}}{\mathop{{{C}_{6}}{{H}_{5}}N{{H}_{2}}}}\,\to \underset{\text{Benzylidene aniline}}{\mathop{{{C}_{6}}{{H}_{5}}CH=N{{C}_{6}}{{H}_{5}}}}\,\]
17.
Consider the following sequence of reactions
\[\text{Compound}\left[ A \right]\xrightarrow{\text{Reduction}}\left[ B \right]\] \[\xrightarrow{HN{{O}_{2}}}C{{H}_{3}}C{{H}_{2}}OH\]
The compound $$[A]$$ is
$$Ortho$$ - substituted anilines are weaker bases than anilines regardless of the nature of the substituent whether electron releasing or electron withdrawing. This is called $$ortho$$ effect and is probably due to a combination of steric and electronic factors.
20.
Best method for preparing primary amines from alkyl halides without changing the number of carbon atoms in the chain is
A
Hofmann bromamide reaction
B
Gabriel phthalimide synthesis
C
Sandmeyer reaction
D
reaction with $$N{H_3}$$
Answer :
Gabriel phthalimide synthesis
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