NJC Polymer Part 1 Tutorial Ans

POLYMERS (Part 1) TUTORIAL Structure and naming 1 Give the IUPAC name for each compound. (a) CH3CH(CH3)CH2CH(OH)CH3 4-methylpentan-2-ol (b) CH2=CHCH=CHBr 1-bromobuta-1,3-diene (c) CH3Cl 1-chloro-4-methylcyclohexane (d) CH3CH(CO2H)CH2CH3 2-methylbutanoic acid 2 Draw the skeletal formula of each compound. (a) 2,2,4-trimethylhexane (b) nona-1,3,5-triene (c) 2,4-dibromomethylbenzene Br Br (d) 4-hydroxylheptan-3-one O OH (e) 1-ethyl-3,3-dimethylcyclopentane (f) 2-amino-3-ethyl-2-methylpentane NH2 3 For each part, the name given is incorrect. Draw the skeletal formula for each and give its correct IUPAC name. (a) 2-ethylpentane 3-methylhexane (b) 2-chloro-2-ethylbut-3-ene 3-chloro -3-methylpent -1-ene Cl (c) 2,3-diethylcyclopentane 1,2-diethylcyclopentane (d) 1,1-dimethy-3-propylhexane

Type of reaction 4 Classify each reaction as addition, elimination, condensation, oxidation , reduction or substitution. (a) CH3CH3 + Br2 ⎯→ CH2BrCH3 + HBr substitution (b) CH2=CHCH3 + Br2 ⎯→ BrCH2CH2BrCH3 addition (c) CH3CH2CH2OH + 2[O] ⎯→ CH3CH2CO2H + H2O oxidation (d) CH3CO2H + 2[H] ⎯→ CH3CHO + H2O reduction (e) condensation (f) elimination Balancing equation for organic redox reaction 5 Balance each equation with either [O] or [H]. Add H2O whenever necessary. (a) CH3CH2OH ⎯→ CH3CHO CH3CH2OH + [O] ⎯→ CH3CHO + H2O (b) CH3CH2CONH2 ⎯→ CH3CH2CH2NH2 CH3CH2CONH2 + 4[H] ⎯→ CH3CH2CH2NH2 + H2O (c) CH3CH=CHCH3 ⎯→ 2CH3CO2H CH3CH=CHCH3 + 4[O] ⎯→ 2CH3CO2H (d) CH3CO2CH3 ⎯→ CH3CH2OH + CH3OH CH3CO2CH3 + 4[H] ⎯→ CH3CH2OH + CH3OH

Constitutional Isomerism (Structural Isomerism) 6 A halogenoalkane has the molecular formula C3H5Cl3. Which are the possible names of the isomers of this compound? 1 1,1,1-trichloropropane 2 1,2,2-trichloropropane 3 2,2,3-trichloropropane A 1, 2 and 3 are correct B 1 and 2 only are correct C 2 and 3 only are correct D 1 only is correct Ans : (B) 1,1,1-trichloropropane Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl 1,1,2-trichloropropane 1,2,2-trichloropropane 1,2,3-trichloropropane Option 3 is wrong, the name should be 1,2,2-trichloropropane. Cis-trans Isomerism 7 How many structural and cis-trans isomers are there in dichloropropene, C3H4Cl2? A 3 B 5 C 6 D 7 Ans : (D) Tips: Draw the structural isomers first by considering -chain isomerism -positional isomerism (no functional isomerism for this qn as the functional groups are fixed to be alkene and halogenoalkane) 1,1-dichloropropene Cl Cl ClCl Cl Cl cis-1,2-dichloropropene trans-1,3-dichloropropene Cl Cl trans-1,2-dichloropropene Cl cis-1,3-dichloropropene Cl Cl 2,3-dichloropropene Cl 3,3-dichloropropene Cl Cl

8 –Farnesene is a constituent of the natural wax found on apples. It is also responsible for the characteristic odour of green apples. –Farnesene How many cis-trans isomers does this molecule have? A 2 B 4 C 8 D 16 Ans : (B) ♦ each C of C