chemistry exampler

Question 1

Best method for preparing primary amines from alkyl halides without
changing the number of carbon atoms in the chain is
(i) Hoffmann Bromamide reaction
(ii) Gabriel phthalimide synthesis
(iii) Sandmeyer reaction
(iv) Reaction with NH3

Answer 1

B

Question 2

Acid anhydrides on reaction with primary amines give ____________.

(i) amide
(ii) imide
(iii) secondary amine
(iv) imine

Answer 2

CO-NH BOND IS amide A

Question 3

Hoffmann Bromamide Degradation reaction is shown by __________.

(i) ArNH2
(ii) ArCONH2
(iii) ArNO2
(iv) ArCH2NH2

Answer 3

B

Question 4

bronsted acid base questions

Answer 4

Question 23. Which of the following compounds is the weakest Bronsted base?
Solution: (c) Amines (a, b) have stronger tendency to accept a proton and hence are
stronger Bronsted bases than phenol (c) and alcohol (d). Since phenol is more acidic than
alcohol, therefore, phenol (c) has the least tendency to accept a proton and hence it is the
weakest Bronsted base

Question 5

exampler Q 23 24

Answer 5

Solution: (d) Aniline is weaker base than NH3 due to delocalization of lone pair of electrons
on the N-atom into the benzene ring. Pyrrole (c) is not at all basic because the lone pair of
electrons on N-atom is donated towards aromatic sextet formation. Therefore, pyrrolidine (d)
has a strong tendency to accept a proton and is hence, the strongest base.

Question 6

The correct decreasing order of basic strength of the following species is \_\_\_\_\_\_\_.
H2O, NH3
, OH
–
, NH2
–

(i) NH2
–
> OH –
> NH3 > H2O

(ii) OH–
> NH2
–
> H2O > NH3

(iii) NH3
> H2O > NH2
– > OH–

(iv) H2O > NH3
> OH
– > NH2
–

Answer 6

(a) NH2 > OH > NH3 > H2O. Due to higher electronegativity of O than N atom, O –
H bond is more polar than N – H bond. Hence, O – H is more acidic in nature than N – H
bond. Now, NH2 and OH have negative charge due to which they are more basic than NH3

Question 7

Which of the following should be most volatile?
(I) CH3CH2CH2NH2

(II) (CH3
)
3N (III) (IV) CH3CH2CH3

(i) II
(ii) IV
(iii) I
(iv) III

Answer 7

(b) 1° and 2° amines have higher boiling points due to intermolecular H-bonding
(and hence less volatile than 3° amines and hydrocarbons of comparable molecular mass).

Question 8

Which of the following should be most volatile?
(I) CH3CH2CH2NH2
(II) (CH3)3N (IV) CH3CH2CH3

(i) II
(ii) IV
(iii) I
(iv) III

Answer 8

(b) 1° and 2° amines have higher boiling points due to intermolecular H-bonding
(and hence less volatile than 3° amines and hydrocarbons of comparable molecular mass).

Question 9

.Which of the following methods of preparation of amines will NOT give same number
of carbon atoms in the chain of amines as in the reactant?
(i) Reaction of nitrite with LiAlH4
.
(ii) Reaction of amide with LiAlH4

followed by treatment with water.
(iii) Heating alkylhalide with potassium salt of phthalimide followed by
hydrolysis.
(iv) Treatment of amide with bromine in aqueous solution of sodium hydroxide.

Answer 9

D NITRILE (R-CN) AMIDE (CO-NH2)

Question 10

C2H5CL+2 NH3

Answer 10

C2H5NH2+ NH4CL

Question 11

Question 36. Under which of the following reaction conditions, aniline gives p-nitro
derivative as the major product?
(a) Acetyl chloride/pyridine followed by reaction with cone. H2SO4 + cone.
(b) Acetic anhydride/pyridine followed by cone. H2SO4 + cone. HNO3
(c) Dil. HCl followed by reaction with cone. H2SO4 + cone. HNO3
(d) Reaction with cone. HNO3 + cone. H2S0

Answer 11

A B

Question 12

NCERT EXAMPLER Q 62 IMP

P NITRO ANILINE TO 345 TRIBROMONITROBENZENE

Answer 12

BR2/CH3COOH 2) NANO2+HCL 3)CU/BR

Question 13

Which of the following reagents can be used to oxidise primary alcohols to
aldehydes?

Answer 13

CRO3

Question 14

20. Phenol can be distinguished from ethanol by the reactions with _________.
    (i) Br2
    /water
    (ii) Na
    (iii) Neutral FeCl3
    (iv) All the above

Answer 14

ans( 1 3)Explanation: Ethanol does not give any reaction with neutral FeCl3 solution while phenol
gives violet color with neutral FeCl3

. When phenol is treated with bromine water, 2,4,6-
tribromophenol is formed as white precipitate. Ethanol does not react with bromine water.

Question 15

what is benzyl alcohol

Answer 15

OH Attachred to sp3 carbon attom

Question 16

what is benzyl alcohol

Answer 16

hybridised carbon atom next to an aromatic ring. For example,

Question 17

The position of –Br in the compound in CH3CH==CHC(Br)(CH3
)
2
can be

classified as ____________.

(i) Allyl
(ii) Aryl
(iii) Vinyl
(iv) Secondary

Answer 17

A

Question 18

q imp rxn of 3phenylpropene with HCL GIVES

Answer 18

2CHLORO3PHENYLPROPENE

Question 19

Which is the correct increasing order of boiling points of the following
compounds?
1-Iodobutane, 1-Bromobutane, 1-Chlorobutane, Butane

Answer 19

Explanation: For the same alkyl group, the boiling points of alkyl halides decrease in the
order: RI>RBr>RCl>RF. This is because with the increase in size and mass of halogen atom,
the magnitude of van der Waal forces increases.

Question 20

31. Which is the correct increasing order of boiling points of the following compounds?
    1-Bromoethane, 1-Bromopropane, 1-Bromobutane, Bromobenzene

Answer 20

1-Bromoethane < 1-Bromopropane < 1-Bromobutane < Bromobenzene

Question 21

ETHYLIDNE CHLORIDE

Answer 21

ch3 c (cl)2h

Question 22

Aryl halides: ?

Answer 22

Aryl halides: These are the compounds in which the halogen atom is bonded to
the sp2- hybridised carbon atom of an aromatic ring.

Question 23

Alkyl fluorides are synthesised by heating an alkyl chloride/bromide in
presence of ____________ or ____________.
(i) Ca F2
(ii) CoF2
(iii) Hg2F2
(iv) NaF

Answer 23

2 3

Question 24

3. When 0.1 mol CoCl3
   (NH3
   )5
   is treated with excess of AgNO3

, 0.2 mol of AgCl are

obtained. The conductivity of solution will correspond to

Answer 24

1:2 no of chloride ion released give the answer