UPTU Previous Year Question Papers B Tech 4th Sem Instrumental and Analytical Chemistry 2006-07

UPTU Previous Year Question Papers B Tech 4th Semester

Instrumental and Analytical Chemistry 2006-07

 

Note : (1) Attempt all questions.

(2) In case of numerical problems assume data wherever not provided.

(3) Be precise in your answer.

1. Attempt any four parts of the following :

(a) What is an auxochrome? Explain how an auxochrome exerts a bathochromic shift on a chromophore such as an ethylenic bond?

(b) What is the basic principle for a spectropho- tometric titration? What are the advantages of such a titration?

(c) Why the A,max for the diene A is observed at lower nm than B? Explain.

 

CH CH B

(d)   What are metastable ions? Explain their utility in confirming a proposed mass fragmentation pattern.

(e) Why are molecular ion peaks either very weak or completely absent from the mass spectrum of many compounds? Explain how this limi­tation can be overcome.

(f)  Explain how spectrophotometry is used in the study of the formation of complexes?

 

2. Attempt any four parts of the following :

(a) Discuss the basic principle of Nuclear Magnetic Resonance spectroscopy.

(b) Giving examples explain equivalent and non­equivalent protons. What is their significance in NMR spectroscopy?

(c) A compound having the molecular formula CgHjj Br gave the following !H NMR data:

8 2.15 (2H, quintet), 82.75 (2H, triplet),

8 3.38 (2H, triplet), 87.22 (5H singlet) Assign the structure to the compound.

(d) 13C is NMR active while 12C is not, explain.

(e) Explain shielding and deshielding of a nucleus in NMR spectroscopy.

(f)  What is Relaxation process in !H NMR spectroscopy? Explain its significance.

 

3. Attempt any two parts of the following :

(a) Giving a schematic sketch discuss the working of the IR spectrometer.

(b) Write short notes on :

(i)  Raman spectroscopy

(ii) Molecular vibrations

(iii) Fundamental vibrations and overtones

(c) How would you distinguish between the com­pounds in each pair by IR spectral studies.

(i)  Phenol and cyclohexanol

(ii) cis and trans 2-Butane

(iii) Acetaldehyde and acetone

 

4. Attempt any two parts of the following :

(a) What are the basic components of the gas chromatograph? Describe each in brief.

(b) Explain the principle of conductometric titrations and various titration curves obtained in acid-base titrations.

(c) (i) Describe the basic principle underlying chromatographic process.

(ii) Explain the terms – half-wave potential, limiting current, DME.

 

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