(Tutor Marked Assignment)
Course Code: CHE- 5
Assignment Code: CHE-5/TMA/2018
All answer below
Maximum Marks: 100
- a) Give the IUPAC names of the following compounds:
- Draw cis and trans- isomers of 1,3-cyclobutanedicarboxylic acid. Comment on the (5) dipole moment of these isomers.
What are racemic mixtures? How are they obtained? Discuss one method of their (5) resolution.
- Give reason for the following:
(i) β-carotene is a red coloured compound.
ii). Carbonyl compounds absorb radiation in the infrared region.
iii). CDCl3 is used as a solvent for recording the NMR spectrum of a compound.
- Arrange the following in the increasing order of their acidic strengths:
propanoic acid, ethanoic acid, 2-fluoroethanoic acid, 2-chloroethanoic acid, dichloroethanoic acid
Also give reason in support of your answer.
- a) Explain the following:
(i) Alkanes with odd number of carbon atoms have low melting point than those with an even number
- Wurtz reaction is not very useful when two different alkyl halides are used.
- b) Describe the following: (3)
(i) Bergius Process
ii). Fischer Process
- a) Explain the following in one to two lines.
(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) Fill in the following blanks:
(i) In the UV spectrum, the ethylenic chromophore shows an absorption band below __________nm.
- a) Arrange the following in the decreasing order of their basic strength:
alkanide anion; alkenide anion; alkynide anion
Justify your answer.
- b) How will you prepare the following ?
(i) 10 -Hexyne from ethyne
(ii) Ethanol from ethyne
(iii) 3-Hexanone from 3-hexyne.
- (a) What is resonance energy? Explain taking the example of benzene. (2½)
(b) What are the limitations of Friedel-Crafts alkylation?
- (a) 2-Position of pyrrole is more reactive towards electrophilic substitution than 3-position. Explain giving all possible resonance structures of carbocations formed. Explain.
(b) Predict the product(s) of the following reactions:
(i) Nitration of azole
(ii) Friedel-Crafts acylation of pyridine
(iii) Reduction of pyrrole with zinc and ethanoic acid.
- Among alkyl halides, order of reactivity of SN2 reaction is
CH3X > p-RX > Sec-RX > tert-RX
Discuss the factors which are mainly responsible for this order.
- Write the chemical equation for following named reactions:
(a) Reimer-Tiemann reaction
(b) Kolbe reaction
(c) Claisen reaction
(d) Knoevenagel reaction
(e) Willgerodt reaction
- Suggest the reaction that can best be used to prepare following ethers by Williamson ether synthesis
(a) CH3CH2 – O - CH = CH2
(b) CH3CH2CH = OCH3
- Explain Hell-Vollhard-Zelinski reaction. Also illustrate its synthetic importance.
- Write chemical reactions for the following:
(i) Kolbe Schmidt reaction
(ii) Strecker synthesis
(iii) Dieckmann cobndensation
(iv) Knoevenagel reaction
(v) Perkin condensation
- Discuss various methods of reduction of esters giving the products formed.
- (a) Why do nitro compounds dissolve in sodium hydroxide?
(b) What is aci form of nitroethane? Discuss.
- What are nucleotides? Draw the structures of nucleotides present in DNA and give their names.