cwiwPwZ ‡gv: gvmyg web Inve cÖfvlK, imvqb wefvM XvKv †iwm‡Wbwmqvj g‡Wj K‡jR
AvR‡Ki cvV mgvYyZv Øv`k †kÖwY
wkLbdj GB cvV †k‡l wkÿv_©xiv Rvb‡Z cvi‡e- mgvYyZv Kx MvVwbK mgvYZv Kx I Zvi kZ© wÎgvwÎK mgvbyZv I Zvi kZ© - Rvb‡Z cvi‡e|
Isomerism/mgvYyZv ‡h mKj †hŠ‡Mi AvbweK ms‡KZ GKB wKš‘ MvVwbK ms‡KZ wfbœ nevi Kvi‡Y Kgc‡ÿ GKwU †fŠZ ev ivmvqwbK a‡g©i cv_©K¨ †`Lvq Zv‡`i †K ci¯ú‡ii Zv‡`i‡K ci¯ú‡ii mgvby e‡j | ‡hmKj †hŠ‡Mi AvbweK I MvVwbK ms‡KZ GKB wKš‘ wÎgvwÎK web¨vm wfbœ nevi Kvi‡Y Kgc‡ÿ GKwU †fŠZ ev ivmvqwbK a‡g©i cv_©K¨ †`Lvq Zv‡`i †K ci¯ú‡ii mgvby e‡j | ‡hŠ‡Mi Giæc ag©‡K mgvYyZv(Isomerism) e‡j |
mgvYyZv Stereoisomers / wÎgvwÎK mgvYyZv Structural isomerism /MvVwbK mgvYyZv Diastereomers not mirror imagesEnantiomers Non-superimposable mirror image
MvVwbK mgvYyZv ‡hŠ‡Mi Abyw¯’Z wewfbœ cigvYy ev g~j‡Ki m¤¢ve¨ GKvwaK Ae¯’vb web¨v‡mi cv_©K¨ †nZz‡h mgvYyZvi D™¢e nq Zv‡K MvVwbK mgvYyZv e‡j |
MvVwbK mgvYyZv wkKj mgvY yZv Ae¯’vb mgvYyZ v Kvh©Kix g~jK mgvYyZv ‡gUvgvw iRg U‡Uvgv wiRg
8 1. wkKj mgvYyZv Kve©b wkK‡ji wfbœZv‡nZz G mgvYyZvi D™¢e nq|
9 1. Chain isomerism C 6 H 14 p.2, Q.2
10 2. Ae¯’vb mgvYyZv GKB Kve©b KvVv‡gv Dcw¯’Z wKš‘ Kvh©Kix g~j‡Ki Ae¯’v‡bi wfbœZvi Kvi‡Y G ai‡bi mgvYyZvi D™¢e N‡U|
11 2. Ae¯’vb mgvYyZv e.g.Butan-1-ol and butan-2-ol (molecular formula: C 4 H 10 O)
12 Wrong ! Q.15 Are they position isomers ? Giv ci¯ú‡ii wkKj mgvYy
13 3.Kvh©Kix g~jK mgvYyZv wfbœ wfbœ Kvh©Kix g~j‡Ki &&&&&&&&&&&&&&Dcw¯’wZi Kvi‡Y &&G ai‡bi mgvYyZvi D™¢e nq|
14 Functional Group Isomerism AlcoholEtherVs C2H6OC2H6O
New Way Chemistry for Hong Kong A-Level Book 3A15 Functional Group Isomerism AldehydeKetoneVs C3H6OC3H6O
New Way Chemistry for Hong Kong A-Level Book 3A16 4. ‡gUvgvwi Rg Kvh©Kix g~j‡Ki &&&&&&&&&&&Dfq cv‡k Kve©b cigvYyi msLvi wfbœZvi Kvi‡b G ai‡bi mgvYyZvi &&&&D™¢e nq|
New Way Chemistry for Hong Kong A-Level Book 3A17 4. ‡gUvgvwiR g e.g.Methoxypropane and ethoxyethane (molecular formula: C 4 H 10 O)
New Way Chemistry for Hong Kong A-Level Book 3A18 4. ‡gUvgvwiR g e.g.Pentan-2-one and pentan-3-one (molecular formula: C 5 H 10 O) can also be considered as position isomers
New Way Chemistry for Hong Kong A-Level Book 3A19 Ae¯’vb mgvYyZv wkKj mgvYyZv C 4 H 10 O
New Way Chemistry for Hong Kong A-Level Book 3A20 5. U‡Uvgvw iRg `ywU wfbœ Kvh©Kix g~j‡Ki g‡a¨ GKwU MwZkxj mvg¨ve¯’v eRvq ZvK‡j G ai‡Yi mgvYyZvi m„wó nq|
New Way Chemistry for Hong Kong A-Level Book 3A21 5. U‡UvgvwiRg ethenol ethanal Bbj – wK‡Uv U‡UvgvwiRg
New Way Chemistry for Hong Kong A-Level Book 3A22 5. U‡UvgvwiRg ethenol ethanal B‡bvj KvVv‡gv‡Z -OH MÖæcwU mivmwi wØeÜb hy³ Kve©‡bi mv‡_ hy³ _v‡K
New Way Chemistry for Hong Kong A-Level Book 3A23 Stereoisomerism wÎgvwÎK mgvYyZv
New Way Chemistry for Hong Kong A-Level Book 3A24 Stereoisomerism †hŠ‡Mi AvbweK I MvVwbK ms‡KZ GKB wKš‘ wÎgvwÎK web¨vm wfbœ nevi Kvi‡Y G ai‡bi mgvYyZvi m„wó nq|
New Way Chemistry for Hong Kong A-Level Book 3A25 Stereoisomerism wÎgvwÎK mgvYyZv `yB ai‡bi : 1.Geometrical isomerism 2.Optical isomerism
New Way Chemistry for Hong Kong A-Level Book 3A26 Geometrical Isomerism C=C double bond. N~Y©b cÖwZeÜKZvB G mgvYyZvi KviY Stereoisomerism
New Way Chemistry for Hong Kong A-Level Book 3A27 Rotation about the axis of a double bond through an angle of 90 o results in the breaking of the π bond maximum overlap of p z orbitals minimum overlap of p z orbitals
New Way Chemistry for Hong Kong A-Level Book 3A28 Geometrical Isomerism - Criteria where a b and c d
New Way Chemistry for Hong Kong A-Level Book 3A29 wmm- UªvÝ mgvYyZv C=C double bond Gi mv‡_ hy³ GKB ai‡bi MÖæc ¸‡jv GKB w`‡K _vK‡j Zv‡K wmm/ cis mgvYy e‡j| C=C double bond Gi mv‡_ hy³ GKB ai‡bi MÖæc ¸‡jv wfbœ w`‡K _vK‡j Zv‡K UªvÝ/ trans mgvYy e‡j|
New Way Chemistry for Hong Kong A-Level Book 3A30 Geometrical Isomers 1,2 dichloro cis-butene-2 trans-butene-2 m.p. 80 C 50 C b.p. 60 C 48 C 1.
Isomers ? Cis - same side Trans - across Cis-trans isomers are also called geometric isomers. There must be two different groups on the sp 2 carbon. No cis-trans isomers possible
New Way Chemistry for Hong Kong A-Level Book 3A32 wKQz geometric isomers mg~‡ni ¸iyZ¡c~Y© chemical properties Gi difference _v‡K 1. K 10 2 mol dm 3 >> 9.3 10 5 mol dm 3 K 10 7 mol dm 3 < 3.6 10 5 mol dm 3
New Way Chemistry for Hong Kong A-Level Book 3A33 Formation of intra-molecular hydrogen bond helps to draw electrons from the –OH Weakening O – H Ease of release of H + H+H+ K 1 : cis > trans
Geometric Isomers in Cycloalkanes Ring structures like C=C restrict rotation and therefore can result in cis and trans isomers 34
New Way Chemistry for Hong Kong A-Level Book 3A35 Optical Isomerism/ Av‡jvK mgvYyZv 35
New Way Chemistry for Hong Kong A-Level Book 3A36 Av‡jvK mgvYyZv ‡h mKj †hŠ‡Mi AvbweK I MvVwbK ms‡KZ GKB wKš‘ wÎgvwÎK web¨vm wfbœ nevi Kvi‡Y GK mgZjxq Av‡jvi cÖwZ wfbœ iæc AvPib K‡i Zv‡`i‡K ci¯ú‡ii Av‡jvK mwµq mgvYy e‡j| 36
New Way Chemistry for Hong Kong A-Level Book 3A37 Av‡jv mwµq mgvYyZvi kZ© AcÖwZmg Kve©b cigvYy _vK‡Z n‡e A_©vr KvBivj Kve©b _vK‡Z n‡e | ‡Kvb Sp 3 carbon atom Gi mv‡_ PviwU wfbœ wfbœ cigvYy ev MÖæc hy³ _vK‡j H Kve©b cigvYywU AcÖwZmg nq|
New Way Chemistry for Hong Kong A-Level Book 3A38 KvBivj Kve©b
New Way Chemistry for Hong Kong A-Level Book 3A39 It is not superimposable with its mirror image A_©vr cimec‡ii Dci AmgcvwZZ n‡Z n‡e mirror
New Way Chemistry for Hong Kong A-Level Book 3A40
New Way Chemistry for Hong Kong A-Level Book 3A41 plane-polarized light Light vibrating in ALL possible planes Light vibrating in only ONE plane
New Way Chemistry for Hong Kong A-Level Book 3A42 Optically active Optically active substance can rotate the plane of polarization of plane-polarized light Measured by a polarimeter.
New Way Chemistry for Hong Kong A-Level Book 3A43 Optically active Dextrorotatory(+) : Nwoi KuvUvi w`‡K N~Y©Y (to the right) Laevorotatory(-): Nwoi KuvUvi wecixZ w`‡K N~Y©Y (to the left) Dc‡ii bg~bvwU Kx Dextrorotatory ? No. It is laevorotatory
New Way Chemistry for Hong Kong A-Level Book 3A44 Enantiomers ( 對映異構體 ) Giv G‡K Ac‡ii `c©Y cÖwZwe¤^ Giv G‡K Ac‡ii Dci Dc¯’vbxq bq Giv GK mgZjxq Av‡jvi Zj‡K GKB cwigv‡Y wKš‘ wecixZ w`‡K †Nvivq
New Way Chemistry for Hong Kong A-Level Book 3A45 g~j¨vqY UviUvwiK Gwm‡Wi KqwU Av‡jvK mwK&ªq mgvYy m¤¢e? Maleic acid I Fumaric acid Gi g‡a¨ †KvbwUi MjYvsK I ùzUYvsK †ewk v‡es †Kb? 45
New Way Chemistry for Hong Kong A-Level Book 3A46 THANKYOU 46