Indira Gandhi National Open University (IGNOU) 2005 B.Sc Chemistry Organic - - Question Paper

CHE-5

BACHELOR OF SCIENCE (B.Sc.) Term-End Examination June, 2005

CHEMISTRY CHE-5 : ORGANIC CHEMISTRY

Time : 2 hours    Maximum Marks : 50

Note : Attempt all the four questions.

1. (a) Give the 1UPAC names of the following

compounds :    1+1

(i)    CH₃CH₂OCH₂CH(CH₃)₂

(ii)    CH₂ CHCOOH

(b) Complete any three of the following reactions : 1x3

RC s CR' -........ BaS0₄, H_z (BH3)₂ (iv)-CH₃ CH = CH₂

H₂0₂, "OH

<v) CH3COOH + NaOH

2. (a) Attempt any two of the following :

[)) Which one out of 1,3-pentadiene or 1,4-pcntadiene will have absorption maximum on longer wavelength and why ?

(ii)    How will you prepare .4-nitrobenzenamine from benzenamine (aniline) ?

(iii)    Write the structure of heterocyclic nucleus present in indole alkaloids and quinoline alkaloids.

(b) Attempt any three of the following :

How will you convert ? ' '

(i)    CH₂ = CH CH₂CICH₂ = CH CH₃

(ii)    A CH₃CH₂CH₂OH

(iii)    CH₃ CH - CH₂ CH₃ CH CH₃ OH (iv)    CH₃C = CCH₃ 2 CH₃COOH

'N'    'N' COCH3

3* Answer any five of the following ;

(a)    Arrive at the configuration of any tu?o of the following molecules using CIP rnles ;

^Br 'x

(i)    /C = C

CK    CH3

OH

I

(ii)    CH₃ C CHO H

COOH

I

(iii)    H C OH

I

HO C H

I

ch₃

(b)    Name the symmetry elements present in any two of the following molecules :

(i)    HC s CH

H.    /CH₃

(ii)    = C CT H₃c

ch₃ ch₃

(c)    What do you understand by ring chain and valence tautomerism ? Cite one example of each,

(d)    Give the reaction of methyl magnesium bromide with

(i)    carbon dioxide

(ii)    methyl'cyanide

(e)    Write the products of the following reactions :

(i)    1-propanol 73 K, Cu _> ?

A

(ii)    2-methylbutanol 573 K, Cu_ _> 

A

What is the importance of the above reactions ?

{0 Give the products obtained when the following acids are heated with a mineral add :

(i)    2-hydroxybutanoic add

(ii)    3-hydroxybutanoic acid

(iii)    4-hydroxybutanoic add

(s) Give the expected products of the reaction between ethyl benzoate and the following reagents :

0) aqueous NH₃, heat

(ii)    LtAlH₄ followed by

(iii)    excess of CH₃MgBr followed by H₃0⁺

(h) How can ethylene oxide be converted into (i) ethanal and (ii) ethane-1,2-diot ?

(a)    What is the fingerprint region in IR spectroscopy ? Give its utility. What are various mediums used in recording IR spectrum ?

(b)    Give the main uses of studying mass spectrum of an organic compound. What are the expected peaks in the mass spectrum of 2,2-dimethylbutane ?

(c)    Which member of each of the following pairs would undergo S2 reaction faster ? Explain.

(Attempt any two) :

CH₂C1    Cl

(i) ^or

(ii)    CH₂ = CHCHCl or CH₃CH₂CH₂a

(iii)    (CH3)₂CHCH₂C1 or (CH₃)₃CC1

(d)'    Write short notes on any two of the following :

(i)    Gattermann synthesis

(ii)    Wittig reaction

(ill) Cannizzaro reaction

(e)    Give two different methods of converting

2-methylpropanoic acid into its methyl ester.

(f)    What is saccharin ? How is it manufactured ? Why has its use been discontinued as a sweetening agent ?

(g)    What is Hofmann rearrangement ? Explain with suitable example.

(h)    What is Reformatsky reaction ? How can

3-methy]-3-hydroxybutanoic acid be prepared from 2-bromoaceUc acid using this region ?

CHE-5    6

Attachment: indira-gandhi-national-open-university--ignou--2005-b-sc-chemistry-55410-1.pdf

Earning:   Approval pending.