NJC Isomerism Tutorial Answer

2Isomerism TutorialProperties of isomers1Two organic isomers are known to contain the same functional group. Assess the following statements about the two molecules.(a)They have the same empirical formula. true / may be true / false(b)They have the same boiling point.true / may be true / falseEnantiomers have same boiling point, however structural isomers & cis-trans isomers have different boiling point. (c)They have the same chemical properties.true / may be true / falseIsomers with same functional group same the same chemical properties. (d)They have the same solubility in water.true / may be true / falseE.g. cis-trans isomers with polar groups may have different polarity (e.g. trans 1,2-chloroethene is non-polar while cis 1,2-dichloroehthene is polar) and could have different solubility in polar solvent.Constitutional Isomerism (Structural Isomerism)2How many isomers of dichlorobenzene are there? (benzene: )A2B 3C 4D5 Cl Cl Cl Cl Cl ClCl Cl Cl Cl1,2-dichlorobenzene 1,4-dichlorobenzene 1,3-dichlorobenzene The 3 isomers are:

3A halogenoalkane has the molecular formula C3H5Cl3. Which are the possible names of the isomers of this compound? 11,1,1-trichloropropane21,2,2-trichloropropane32,2,3-trichloropropaneA 1, 2 and 3 are correctB1 and 2 only are correctC2 and 3 only are correctD1 only is correct 1,1,1-trichloropropaneClClCl ClClCl ClCl ClClCl Cl1,1,2-trichloropropane1,2,2-trichloropropane1,2,3-trichloropropaneCis-Trans Isomerism4How many structural and cis-trans isomers are there in dichloropropene,C3H4Cl2?A3B 5C 6D7 1,1-dichloropropeneClClClClClClcis-1,2-dichloropropenetrans-1,3-dichloropropene ClCltrans-1,2-dichloropropeneClcis-1,3-dichloropropeneCl Cl2,3-dichloropropeneCl3,3-dichloropropeneCl Cl

5–Farnesene is a constituent of the natural wax found on apples. It is also responsible for the characteristic odour of green apples.–FarneseneHow many cis-trans isomers does this molecule have?A2B 4C 8D16 each C of C=C (C3, C4 and C5, C6) has 2 different groups attached no of cis-trans isomers = 22 = 46Low fat sunflower spreads which are high in polyunsaturated contain esters of linoleic acid.CH3(CH2)4CH=CHCH2CH=CH(CH2)7CO2HOn the lid of a brand of spread, it is claimed that the spread contains virtually no trans fatty acid. Which isomer does not contain a trans linkage that could be present in the spread?ACCCH3(CH2)4HCCH2C(CH2)7CO2HHHH CCCH3(CH2)4HCCH2C(CH2)7CO2HHHtranstransHBCCHCCH2C(CH2)7CO2HHHHCH3(CH2)4 CCHCCH2C(CH2)7CO2HHHHCH3(CH2)4transcisCCCCH3(CH2)4HCC(CH2)7CO2HHCH2HH CCCH3(CH2)4HCC(CH2)7CO2HHCH2HHciscisDCCHCC(CH2)7CO2HHCH2CH3(CH2)4HH transcisCCHCC(CH2)7CO2HHCH2CH3(CH2)4HH 12 56891011

Optical Isomerism (Enantiomerism)7The drug cortisone has the formula shown. O CH3O CH3COHOCH2OH * OCH3OCH3COHOCH2OH*****cortisoneHow many chiral centers are present in each cortisone molecule?A3B 4C 5D68What is the maximum number of stereoisomers for the molecule shown below? CH3CH3 CH3 CH(OH)CH3 O H3C O CH3 * * * * ** CH3CH3 CH3 CH(OH)CH3 O H3C O CH3 *