What is tautomerism explain briefly any two types of

Question

Question 1. (a) Give the IUPAC names of the following compounds:

(i) 

(ii) CH₂ = CHCH₂CHO

(iii) 

(b) Write the structures of the following compounds:
(i) 3, 4-Dibromo-2-pentanone
(ii) Butyl benzoate

Question 2. (a) Write the geometrical isomers of 2-butene and also designate them as E/Z isomers.

(b) What are various elements of symmetry? Give one example illustrating the presence (3) of such elements in them.

Question 3. Using a suitable diagram, explain the relative energies of various conformations of (5) cyclohexane.

Question 4. Explain the following terms:

(i) Auxochrome
(ii) Fingerprint region
(iii) Chemical shift
(iv) Chemical exchange
(v) Molecular ion

Question 5. What is tautomerism? Explain briefly any two types of tautomerism using suitable (5) examples.

Question 6. a) How would you prepare alkanes from the following (Give only one example)?
(i) Alkyl halide
(ii) Carboxylic acid
(iii) Alkene
b) Explain the following:
(i) In the mass spectra, alkanes give a series of peaks separated by 14 mass units.
(ii) Alkanes with odd number of carbon atoms have lower melting point than those with an even number of carbon atoms.

Question 7. a) Explain the following briefly:
(i) Alkenes are more soluble in water than corresponding alkanes.
(ii) Addition reactions of alkenes are exothermic processes.
(iii) Hydroboration appear as anti-Markownikoff's addition.
b) An alkene having molecular formula C6H12 an ozonolysis yielded butanal and (2) ethanal. What is the structural formula of alkene?

Question 8. a) Explain the following:
(i) Alkynes are more acidic than alkanes.
(ii) In NMR, the value of alkynyl proton is less than the value of alkenyl proton.
b) How would you prepare the following?
(i) 3-Octyne from 1-hexyne
(ii) 1,2-Dibromoethene from ethyne
(iii) Ethanal from ethyne

Question 9. a) Explain the following:
(i) The theoretical value of heat evolved, when hydrogens are added to benzene, is quite high as compared to the experimental value.
(ii) Nitrobenzene not undergo Friedel-Crafts alkylation.
b) Write all the possible resonance structures of cation formed from ortho nitration (1) of methyl benzene.
c) What do you understand by para-directing activators, para- directing deactivators (2) and meta-directing deactivators?

Question 10. a) Explain the following:
(i) 1-Position in naphthalene is more reactive than the 2-position towards electrophilic substitution.
(ii) Pyrrole is more basic than pyridine.
b) Predict the products of the following reactions:
(i) Oxidation of propylbenzene
(ii) Friedel-Crafts acylation of pyrrole
(iii) Friedel-Crafts alkylation of pyridine

Question 11. Complete the following reactions. Predict whether each reaction proceeds (5) predominantly by SN1 or SN2 or E1 or E2.

Question 12. Complete the following reaction and write its mechanism.

 

Question 13. Taking suitable examples discuss the Zeisel procedure used for estimation of (5) methoxy group in alkyl aryl ethers.

Question 14. Write the chemical reactions for the different methods used for the reduction of (5) aldehydes and ketones.

Question 15. Explain Fischer esterification with the help of a suitable example.

Question 16. Give the products of the following reactions:

(i) CH₂ = CHCOOH  →^HBr ?

(ii) HOOCCH₂COOH ^Δ→_423K ?

(iii) V₂O₅ →? ^hydrolysis→ ?

(iv) CH₂CH₂CN → H⁺/H₂O

(v) CH₃CHClCH₂COOH → KOH?

Question 17. Explain the following reactions using suitable examples:

(i) Rosenmund reduction
(ii) Transesterification

Question 18. Give the products of reduction of nitrobenzene under acidic, alkaline and neutral (5) conditions.

Question 19. Explain the following reactions and their utility:
(i) Sandmeyer reaction
(ii) Diazo coupling

Question 20. Illustrate Edman degradation and explain its importance.