Nitrogen Containing Compound 1.
[AIEEE-2002]
Picric acid is COOH
OH
COOH
NO2
NO2
(1)
(2)
COOH
(3*)
NO2
NO2
O2N
(4)
OH NO2
NO2
Sol.
It is 2, 4, 6-trinitrophenol.
2.
When primary ami ne reacts with with chloroform in ethanolic KOH then the product is [AIEEE [A IEEE 2002] 2002] (1*) an isocyanide (2) an aldehyde (3) a cyanide (4) an alcohol. C2H5NH2 + CHCI3 + 3KOH C2H5N C + 3KCl + 3HCI Ethyl isocyanide ¼ , f Fky vkb vkbl ksl k; ukbM kbM½
Sol. 3.
[AIEEE [A IEEE 2002] 2002] (4*) both (1) and (2).
The functional group, which is found in amino acid is (1) – COOH group (2) – NH 2 gr group (3) – CH3 gr group
Sol.
An amino acid is a bifunctional organic molecule that contains both groups, groups, –COOH, as well as an amine group, –NH2.
4.
The correct order of increasing basic nature for the bases NH3, CH3NH2 and (CH 3)2 NH is
Sol.
5.
Sol.
(1) CH3NH2 < NH3 < (CH 3)2NH (2) (CH 3)2NH < NH 3 < CH CH3NH2 (3*) NH3 < CH3NH2 < (CH 3)2NH (4) CH 3NH2 < (CH 3)2NH < NH 3. Except the amines amin es containing tertiary butyl group, all lower aliphatic amines are stronger stronger bases than ammonia becaues of + I (inductive). The alkyl groups, which are electron releasing groups, increase the electron density around the nitrogen by increasing the avabil ity of the lone pair of electrons to proton or lewis acids and making the amine more basic. The observed order in the case of l ower members is found more basic. The observed order in the case of lower members is found to be as secondary > primary > tertiary. This anomolous behaviour or tertiary amines is due to steric factors i.e., crowding of alkyl groups cover nitrogen atom from al l sides and thus makes it unable for protonation. Thus the relative strength strength is in i n order, (CH3)2 NH > CH 3NH2 > NH3. Ethyl isocyanide on hydrolysis in acidic medium generates [AIEEE [A IEEE 2003] 2003] (1* (1*) eth ethyl ylam amin ine e sal saltt an and me methan thanoi oic c aci acid d (2) (2) pr propan opanoi oic c aci acid d and and ammo ammoni niu um sa salt (3) ethanoic acid and ammo mmonium ium salt (4) methy thylami lamin ne salt and etha thanoic acid. id. Alkyl isocyanides are hydrolysed by dilute mineral acids to form primary amines. C2H5N
C + 2H2O
H
C2H5NH2 + HCOOH
ethylisocyanide 6.
ethylamine
methanoic acid [AIEEE-2003]
The reaction of chloroform with alcoholic KOH and p-toluidine forms (1)
H3C
CN
(2)
(3)
H3C
NHCHCl 2
(4*)
Sol.
+ CHCl 3 + 2KOH CH3
H3C
H3C
N2Cl
NC
N= C
NH2
7.
[AIEEE [A IEEE 2003] 2003]
+ 3KCl + 3H2O ; This is carbylamine reaction.
CH3
The ammonia evolved ev olved from f rom the treatment of 0.30 g of an organic compound for the estimation of nitrogen was passed in 100mL of 0.1 M sulphuric acid. The excess of acid required 20 mL of 0.5 M sodium hydroxide solution for complete neutralization. [AIEEE [A IEEE 2004] 2004] The organic compound is (1) acetamide (2) benzamide (3*) urea (4) thiourea. AIEE E_Ni tr og eno us Com po un ds -1
Sol.
Equivalents Equival ents of NH3 ev evolved
=
100 0.1 2 1000
20 0.5 1000
Precent of nitrogen in the unknown unknown organic compound Percentage of nitrogen in urea (NH2)2CO =
8.
1
100
1 14 100 100 0.3
46.6
14 2 ×100 = 46.6 60
The compound must mu st be urea. [AIEEE [A IEEE 2004] 2004]
Which Whi ch of the foll owing is the strongest strongest base?
(1)
(2)
(3)
(4*)
. .
Sol.
Lone pairs of N are not taking part in conjugation where as in other other parts lone pairs are taking part in conjugation.
9.
Which Whi ch one of the following methods is neither meant for the synthesis synthesis nor for separation of amines ? [AIEEE [A IEEE 2005] 2005] (1) Hin Hins sberg me method (2) Ho Hofmann method (3*) Wu Wurtz re reaction (4) Cu Curtius ius reaction
Sol.
In Wurtz reaction alk yl halide reacts with sodium metal in the presence of dry ether to give alkane.
10.
Reaction of cyclohexanone with dimethylamine in the presence of catalytic amount of an acid forms a compound is generally known as [AIEEE [A IEEE 2005] 2005] (1) a Schiff’s base (2*) an enamine (3) an imine (4) an amine
Sol. 11.
Sol.
NH2
+
NaNO2 dil. HCl O 5º C
12. Sol.
13.
[AIEEE-2006]
Fluorobenzene (C6H5F) can be synthesized in the laboratory (1*) from aniline by diazotisation foll owed by heating the diazonium diazonium salt with HBF4 (2) by direct fluorination of benzene with F 2 gas gas (3) by reacting bromobenzene with NaF solution (4) by heating phenol with HF and KF N
F
+
–
NCl
HBF4
N
– 4
NBF
+ N2+ BF BF3
Which Whi ch one of the following is the strongest base in aqueous solution? [AIEEE [A IEEE 2007] 2007] (1*) Dimethylamine (2) Methylamine (3) Trimethylamine (4) Aniline The increasing order of basicity of the given compounds is (CH3)2 NH > CH 3NH2 > (CH3)3 N > C6H5NH2 Due to the +I ef fect of alkyl groups the electron density on nitrogen increases increases and thus the abailability of the lone pair of electrons to proton increases and hence the basicity of amines also increases. So aliphatic amines are more basic than aniline. In case of tertiary amine (CH 3)3 N, the covering of alkyl groups over nitrogen atom from al l sides makes the approach and bonding by a proton relativly difficult, hence the basicity decreases. Electron withdrawing (C6H5 –) groups decreases electron density on nitrogen atom and thereby decreasing basicity. In the chemical reaction, [AIEEE-2007, 3/120] CH3CH2NH2 + CHCl 3 + 3 KOH respectively y: (A) + (B) + 3H 2O, the compounds (A) and (B) are respectivel (1) C2H5CN and 3KCl (2) CH3CH2CONH2 and 3KCl (3) C2H5NC and K 2CO3 (4*) C2H5NC and 3KCl AIEE E_Ni tr og eno us Com po un ds -2
Sol.
CH3CH2 –NH2 + CHCl 3 + 3KOH This is carbylamine reaction. Correct cho ice (4) (4)
14.
Presence of a nitro group in a benzene ring [AIEEE-2007, 3/120] (1) activates activ ates the ring towards electrophilic substitution (2) renders the ring basic (3) deactivates the ring t owards owards nucleophilic substitution. (4*) deactivates the ring towards electrophilic substitution. –NO2 group in benzene ri ng shows shows – and – R effect, which deactiv ates the ring towards electrophilic electrophilic substitution but activates it towards nucleophilic substitution. Correct cho ice (4) (4)
Sol.
15.
C2H5 – N
C = 3KCl + 3H 2O
The electrophile, E . attacks the benzene ring to generate the intermediate -complex. Of the following, which s-complex is of lowest energy ? [AIEEE-2008, 3/105]
H
(1*)
H
E
+
NO2
NO2
NO2
(2)
+
E
+
(3)
+
H E
16.
(4) H
E
[AIEEE-2010, 4/144]
In the chemical reactions : NH2
NaNO HCl, 278 K
HBF
4 2 B A
the compounds ‘A” and ‘B’ respectiv respectively ely are (1) nitrobenzene an and fluorobenzene (3*) (3*) benz benzen ene e diaz diazon onium ium chlor chloride ide and and fluo fluoro robe benz nzen ene e
Sol.
NaNO
HCl
2
(2) phenol and benzene (4) (4) nitr nitrob oben enze zene ne and and chlo chloro robe benz nzen ene e
HBF
4
278 K
AIEE E_Ni tr og eno us Com po un ds -3
