Organic Compounds Containing Nitrogen — Page 4 | JEE Chemistry

Q31

Identify correct statements : (A) Primary amines do not give diazonium salts when treated with

\mathrm{NaNO}_2

in acidic condition. (B) Aliphatic and aromatic primary amines on heating with

\mathrm{CHCl}_3

and ethanolic KOH form carbylamines. (C) Secondary and tertiary amines also give carbylamine test. (D) Benzenesulfonyl chloride is known as Hinsberg's reagent. (E) Tertiary amines reacts with benzenesulfonyl chloride very easily. Choose the correct answer from the options given below :

A (B) and (C) only

B (D) and (E) only

C (A) and (B) only

D (B) and (D) only

Correct Answer

Option D

Solution

(A) $\mathrm{R}-\mathrm{NH}_2 \xrightarrow[\mathrm{HCl}]{\mathrm{NaNO}_2} \mathrm{R}-\mathrm{N}_2^{\oplus} \mathrm{Cl}^{\ominus}$ (B) (C) Only primary amine gives carbyl amine test (D) (E) Tertiary amine do not react with $\mathrm{Ph}-\mathrm{SO}_2 \mathrm{Cl}$ So correct options are (B) and (D) only

Q32

Match with $,$ \Delta$$

List - I		List - II
(B)	Clemenson reduction	(II)	$\mathrm{CHCl_3,NaOH/H_3O}$ $^ \oplus$
(C)	Cannizaro reaction	(III)	$\mathrm{Br_2,NaOH}$
(D)	Reimer-Tiemann Reaction	(IV)	$\mathrm{Zn-Hg/HCl}$

A (A) - III, (B) - IV, (C) - I, (D) - II

B (A) - II, (B) - IV, (C) - I, (D) - III

C (A) - III, (B) - IV, (C) - II, (D) - I

D (A) - II, (B) - I, (C) - III, (D) - IV

Correct Answer

Option A

Solution

.tg .tg Reaction Reagents (A) $\begin{aligned} & \text{ Hoffmann } \\ & \text{ degradation }\end{aligned}$ $\longrightarrow$ $\mathrm{Br}_{2}, \mathrm{NaOH}$ (B) $\begin{aligned} & \text{ Clemenson } \\ & \text{ reduction }\end{aligned}$ $\longrightarrow$ $\mathrm{Zn}-\mathrm{Hg} / \mathrm{HCl}$ (C) $\begin{aligned} & \text{ Cannizaro- } \\ & \text{ reaction }\end{aligned}$ $\longrightarrow$ Conc.

$\mathrm{KOH}, \Delta$ (D) $\begin{aligned} & \text{ Reimer-Tiemann } \\ & \text{ reaction }\end{aligned}$ $\longrightarrow$ $\begin{aligned} & \mathrm{CHCl}_{3}, \\ & \mathrm{NaOH} / \mathrm{H}_{3} \mathrm{O}^{+}\end{aligned}$ $\therefore$ Correct match is : (A)-III, (B) -IV, (C) -I, (D)-II

Q33

The gas leaked from a storage tank of the Union Carbide plant in Bhopal gas tragedy was:

A Methylamine

B Ammonia

C Phosgene

D Methyl isocyanate

Correct Answer

Option D

Solution

Methyl isocyanate

C{H_3} - N = C = O

Q34

The correct order of basic nature in aqueous solution for the bases

\mathrm{NH}_3, \mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2, \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2,\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}

and

\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}

is :

A

\mathrm{NH}_3<\mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}

B

\mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2<\mathrm{NH}_3<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}

C

\mathrm{NH}_2-\mathrm{NH}_2<\mathrm{NH}_3<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}

D

\mathrm{NH}_3<\mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}<\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}

Correct Answer

Option C

Solution

Basic strength of amine depends on hydrogen bonding and electronic inductive effect.

$\mathrm{NH}(\mathrm{Et})_2>\mathrm{N}(\mathrm{Et})_3>\mathrm{NH}_2 \mathrm{Et}>\stackrel{\bullet\bullet}{\mathrm{NH}_3}>\mathrm{NH}_2-\mathrm{NH}_2$

Q35

Which one of the following is the strongest base in aqueous solution?

A Trimethylamine

B Aniline

C Dimethylamine

D Methylamine

Correct Answer

Option C

Solution

NOTE : Aromatic amines are less basic than aliphatic amines. Among aliphatic amines the order of basicity is

{2^ \circ } > {1^ \circ } > {3^ \circ }.

The electron density is decreased in

{3^ \circ }

amine due to crowing of alkyl group over

N

atom which makes the approach and bonding by a proton relatively difficult.

Therefore the basicity decreases.

Further Phenyl group show

- {\rm I}

effect, thus decreases the electron density on nitrogen atom and hence the basicity. $\therefore$ dimethylamine (

{2^ \circ }

aliphatic amine) is strongest base among gtiven choices.

$\therefore$ The correct order of basic strength is Dimethyl amine

>

Methyl amine

>

Trimethyl-amine

>

Aniline.

Q36

In the Hofmann bromamide degradation reaction, the number of moles of NaOH and Br2 used per mole of amine produced are:

A Four moles of NaOH and two moles of Br2.

B Two moles of NaOH and two moles of Br2

C Four moles of NaOH and one mole of Br2

D One mole of NaOH and one mole of Br2

Correct Answer

Option C

Solution

4

moles of

NaOH

and one mole of

B{r_2}

is required during production of one mole of amine during Hoffmann's bromamide degradation reaction.

Q37

Ammonolysis of Alkyl halides followed by the treatment with NaOH solution can be used to prepare primary, secondary and tertiary amines. The purpose of NaOH in the reaction is :

A to remove acidic impurities

B to remove basic impurities

C to activate NH3 used in the reaction

D to increase the reactivity of alkyl halide

Correct Answer

Option A

Solution

During the reaction HX (acid) is formed Hence, we use NaOH to remove these acidic impurities

Q38

The correct order of increasing basic nature for the bases NH3, CH3NH2 and (CH3)2 NH is

A (CH3)2NH < NH3 < CH3NH2

B NH3 < CH3NH2 < (CH3)2NH

C CH3NH2 < (CH3)2NH < NH3

D CH3NH2 < NH3 < (CH3)2NH

Correct Answer

Option B

Solution

The alkyl groups are electron releasing group

\left( { + {\rm 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

Q39

Given below are two statements: Statement I : Pure Aniline and other arylamines are usually colourless. Statement II : Arylamines get coloured on storage due to atmospheric reduction. In the light of the above statements, choose the most appropriate answer from the options given below :

A Both Statement I and Statement II are correct

B Statement I is correct but Statement II is incorrect

C Both Statement I and Statement II are incorrect

D Statement I is incorrect but Statement I is correct

Correct Answer

Option B

Solution

The most appropriate answer is Statement-I is correct but Statement-II is incorrect.

Pure Aniline and other arylamines are usually colorless, which is in agreement with Statement-I.

However, Statement-II is incorrect as arylamines do not get colored on storage due to atmospheric reduction.

Instead, get coloured on storage due to atmospheric oxidation and become darker in color upon exposure to air.

Q40

When a concentrated solution of sulphanilic acid and 1-naphthylamine is treated with nitrous acid

(273 \mathrm{~K})

and acidified with acetic acid, the mass

(\mathrm{g})

of 0.1 mole of product formed is : (Given molar mass in

\mathrm{g} \mathrm{mol}^{-1} \mathrm{H}: 1, \mathrm{C}: 12, \mathrm{~N}: 14, \mathrm{O}: 16, \mathrm{~S}: 32

)

A 330

B 33

C 343

D 66

Correct Answer

Option B

Solution

0.1 mole of red-azo dye $($ Molar Mass $=327 \mathrm{gm} / \mathrm{mol})$ will have 32.7 gm mass. Nearly 33 gm .