2022-2023 1st Term Final Organic Chemistry Exam (Biotechnology) PDF

Department: Biochemistry Academic year: 2022/2023 Semester: 1st Program: Biotechnology Level: 1 Course title: Organic Chemistry Course code:101 ABC Date : 10/01/2023 Period: 1st...

Department: Biochemistry Academic year: 2022/2023 Semester: 1st Program: Biotechnology Level: 1 Course title: Organic Chemistry Course code:101 ABC Date : 10/01/2023 Period: 1st Allowed time: Two hours Pages No.: 8 Answer all the following questions: Part I: (30 marks) Q1: Why this alcohol molecule (Tri Phenyl Methanol) cannot form an ester? STERIC EFFECT Q2: Why 4- Chloro 2 Butenoic is strong acid ? Cl-CH2-CH=CH-COOH 1-(Cl ) HIGH Electronegativity Attract electrons between O &H IN COOH ( OxxH ) increase Ionization of H+ 2-Double Bond( CH=CH ) make good bridge for attraction of electrons Q3: Arrange the following pairs in order of increasing Melting point, giving your reasons. ≤ Ortho Para Intra-molecular H Bond inter- molecular H Bond Inside the molecule Between 2 molecule 1/ 9 Q4: What are the hybridization of the carbon (C) atoms labeled with stars (*) in the following molecule? From left to right (C*H3) SP3 INSIDE BENZENE RING ( C* ) IS SP2 C≡C*H IS SP1 Q5: What Type of Isomerization: (Positional , Geometrical ,Chain, Functional group). No ISOMER 1 ISOMER 2 Type of Isomerization 1 Chain CH3-CH2CH2CH2CH3 2 Geometrical 3 Positional 4 CH3-O-CH3 CH3-CH2-OH Functional group 5 HC≡C-CH2-CH3 CH3- C≡C –CH3 Positional 2/ 9 Q6: What Type of Organic Reaction: Substitution (SN, SE, Free Radical), Elimination, Addition, Oxidation- Reduction, Decomposition, Rearrangement. No REACTION TYPE C6H5-H +HNO3(Conc)→(H2SO4 Conc) → C6H5- SE 1 NO2 2 HC≡CH + 2 HBr → CH₃---CH Br₂ Addition 3 CH4 + Cl2 → ( LIGHT)→ CH3-Cl + HCl Free Radical 4 CH3-CH2OH + KMnO4 → CH3-COOH Oxidation 5 CH3-CO-NH2 + KOBr → CH3-NH2 +CO2 Decomposition 6 CH3-CH2-Br + KOH (Alc)→CH2=CH2 Elimination CH3-CH2-COOH +NaOH+CaO(Soda Lime) →CH3- 7 Decomposition CH3 8 CH3-CH2-Br + Na O CH3 → CH3-CH2-O-CH3 +NaBr SN Q7: Why These Radicals are Stable -- 1- Cl-CH2— CH2 Cl is High electronegativity atom attract electrons and decrease the negative charge on ( CH2-- ). 2- CH3-CH2— CH2+ ( CH3-CH2 --- ) good repletion and equalize the positive charge on ( CH2+ ). 3/ 9 Q8: WHY THESE RADICALS are not stable 1- F-CH2— CH2+ ( ) High electronegativity atom attracts electrons and increases the positive F charge ( CH2+ ) 2- Br-CH2— CH2. High electronegativity atoms attracts electrons and increase the ( Br ) poverty of electrons in free radical ( CH2. ) Q9: EXPLAIN Why 1,4 Pentadiene Cannot have Resonance. CH2=CH—CH2—CH==CH2 4/ 9  Non-Conjugated System ( CH2 is SP3 ) steric effect for Resonance Q10: Why Methanal { } faster in the reaction with (HCN) than Acetophenone { } Acetophenone has Steric Effect ( HAS 2 BIG BENZENE RING ) Methanal (HAS 2 SMALL H atoms )easy to react with HCN addition reaction 5/ 9 Part II: (30 marks) Q1: Answer all the following questions using the compounds in the following table (20 marks) CH3CΞCCH3 3 2 1 CH3CH2-SH 6 5 4 CH3CH2CH2CH3 CH3CH2CH2CH2OH CH3CH2CH2NH2 9 8 7 CH3MgCl 12 11 11 1- Identify the catalyst used to prepare compound (1) from compound (2)? Lindeler catalyst 2- Which of the compounds No. (3, 4, or 5) produces a secondary alcohol when treated with compound )21( 4 3- What is the oxidation product of 2 molecules of compound)6( CH3CH2-S-SCH2CH3 4- What is the product of the oxidation of compound (4) with chromic acid (H2CrO4) Acetic Acid 5- Deduce the product of the reaction of compound (7) with one molecule of compound )22( CH3CH2CH2NH-CH3CH2-OH 6/ 9 6- What is the compound that when treated with Ozone gives compounds (4 and 5) 7- What is the product of the reduction of compound (5) by sodium borohydride (NaBH4) 8- Write 4 products only when reacting compound (9) with HNO3 CH3CH2CH2CH2-NO3 + CH3CH2CH2-NO3 + CH3CH2-NO3 + CH3-NO3 9- Write the ester structure formed by the reaction between compounds (8 and 10) 10- Deduce the formed corresponding alkene when treat compound (8) by H2SO4/170 ⁰C CH3CH2CH=CH2 7/ 9 Q2: Answer the following questions using the compounds in the following table (21 marks) 4 3 2 1 8 7 6 5 12 11 10 9 1- Which of the compounds (1, 2, 5, 9) are Aromatic, Antiaromatic, Nonaromatic? Give reason for each one. 1- Aromatic 2- Antiaromatic 5- Nonaromatic 9- Aromatic 2- Which of the two compounds (3 or 6) is more aromatic, with an explanation of the reason? No 6 Bec. n= 1 while in No 3 n=2 (Higher n less aromatic) 3- Which of the two compounds (4 or 8) is more basic, with an explanation of the reason No 4 Bec the lone pair electrons not involved in the π system of the ring 8/ 9 4- Which of the two compounds (7 or 10) is more stable, with an explanation of the reason No 7 Bec. Compound No 7 is aromatic while No 10 is antiaromatic 5- Show the effect of treating compounds (11 and 12) with bromine (Br2). No 11- No 12- With our Best Wishes, Prof.Dr. Awad Abas Ragb Prof.Dr. Sayed A. Fayed Signature: ……………… ……………… Exam reviewer : Prof.Dr. Ghada I. Mahmoud Signature: …………… 9/ 9