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.
71.
Which of the following reactions is appropriate for converting acetamide to methanamine?
A
Carbylamine reaction
B
Hofmann hypobromamide reaction
C
Stephens reaction
D
Gabriels phthalimide synthesis
Answer :
Hofmann hypobromamide reaction
The conversion of amide with no substituent on nitrogen to an amine containing one carbon less by the action of alkaline hypobromide or bromine in presence of $$NaOH.$$ It involves the migration of alkyl or aryl group with its electron pair to electron deficient $$N$$ from adjacent carbon. The reaction involves the intermediates of isocyanate.
\[\text{Step V:}\,C{{H}_{3}}NCO+2O{{H}^{-}}\xrightarrow{\Delta }\] $$C{H_3}N{H_2} + CO_3^{2 - }$$
72.
IUPAC name of the compound $${\left( {C{H_3}} \right)_2}NC{H_3}$$ is
A
2, 2-dimethylmethanamine
B
$$N,N$$ -dimethylmethanamine
C
$$N$$-ethyl-$$N$$-methylethanamine
D
$$N$$-methylpropanamine
Answer :
$$N,N$$ -dimethylmethanamine
\[C{{H}_{3}}\overset{\begin{smallmatrix}
\,\,\,\,\,\,C{{H}_{3}} \\
\,|
\end{smallmatrix}}{\mathop{-N-}}\,C{{H}_{3}}\]
IUPAC name is $$N, N$$ -dimethyl methanamine ( $${3^ \circ }$$ amine ).
73.
Acid anhydrides on reaction with primary amines give
A
amide
B
imide
C
secondary amine
D
imine
Answer :
amide
74.
Which of the following does not represent the correct reaction?
75.
Amides can be converted into amines by a reaction named after
A
Perkin
B
Claisen
C
Hofmann
D
Kekule
Answer :
Hofmann
Amides can be converted into amines by Hofmann's bromamide reaction. This reaction is named after Hofmann. The reaction is as follow.
$$ - CON{H_2} + B{r_2}\left( l \right) + 4KOH \to - N{H_2} + 2KBr + {K_2}C{O_3} + 2{H_2}O$$
76.
Hofmann brornamide degradation reaction is shown by __________.
A
$$ArN{H_2}$$
B
$$ArCON{H_2}$$
C
$$ArN{O_2}$$
D
$$ArC{H_2}N{H_2}$$
Answer :
$$ArCON{H_2}$$
No explanation is given for this question. Let's discuss the answer together.
77.
The shape of $${\left( {C{H_3}} \right)_3}N$$ is pyramidal because
A
nitrogen forms three $$s{p^3}$$ hybridised sigma bonds with carbon atoms of methyl groups and there is one non-bonding electron pair
B
nitrogen forms three $$s{p^2}$$ hybridised sigma bonds with carbon atoms of methyl groups and fourth orbital forms $$pi$$ bond
C
nitrogen has five valencies which are arranged in pyramidal shape
D
the unpaired electron present on nitrogen is delocalised.
Answer :
nitrogen forms three $$s{p^3}$$ hybridised sigma bonds with carbon atoms of methyl groups and there is one non-bonding electron pair
No explanation is given for this question. Let's discuss the answer together.
78.
The strongest base among the following is
A
$${C_6}{H_5}N{H_2}$$
B
$$p{\text{ - }}N{H_2}{C_6}{H_4}N{H_2}$$
C
$$m{\text{ - }}N{O_2}{C_6}{H_4}N{H_2}$$
D
$${C_6}{H_5}C{H_2}N{H_2}$$
Answer :
$${C_6}{H_5}C{H_2}N{H_2}$$
$${C_6}{H_5}C{H_2}\ddot N{H_2}$$ is the strongest base since the lone pair on nitrogen is not involved in conjugation.
79.
Acetamide is treated with the following reagents separately. Which one of these
would yield methyl amine?
A
$$\frac{{NaOH}}{{B{r_2}}}$$
B
$${\text{Sodalime}}$$
C
$${\text{Hot}}\,\,conc.\,{H_2}S{O_4}$$
D
$$PC{l_5}$$
Answer :
$$\frac{{NaOH}}{{B{r_2}}}$$
Key Idea The reagent which can convert $$ - CON{H_2}$$ group into $$ - N{H_2}$$ group is used for this reaction.
Among the given reagents only $$\frac{{NaOH}}{{B{r_2}}}$$ converts $$ - CON{H_2}$$ group to $$ - N{H_2}$$ group, thus it is used for converting acetamide to methyl amine. This reaction is called Hoffmann bromamide reaction, in which primary amides on treatment with $$\frac{{B{r_2}}}{{NaOH}}$$ form primary amines.
$$\mathop {C{H_3}CON{H_2}}\limits_{{\text{Acetamide}}} + NaOH + B{r_2}$$ $$ \to \mathop {C{H_3}N{H_2}}\limits_{{\text{Methyl amine}}} + NaBr + N{a_2}C{O_3} + {H_2}O$$
80.
An organic compound $$(A)$$ on reduction gives
compound $$(B).$$ $$(B)$$ on treatment with \[CHC{{l}_{3}}\] and
alcoholic $$KOH$$ gives $$(C).$$ $$(C)$$ on catalytic reduction gives $$N$$ - methylaniline. The compound $$A$$ is