Organic Chemistry I: Introduction & Alkanes Questions PDF (2020/2021 Past Paper)

# Organic Chemistry I ## Introduction & Alkane Questions **1st year** **Pharm D.** ### Follow us on - Telegram channel: @Medical_SelfLearning ### Dr.HZM - Join us on facebook - Account -> Hazem Mohamed - Group -> FOPCU 2026 - Dr/HZM ## Introduction & Alkanes Questions ### 1- Write True (T) f...

# Organic Chemistry I ## Introduction & Alkane Questions **1st year** **Pharm D.** ### Follow us on - Telegram channel: @Medical_SelfLearning ### Dr.HZM - Join us on facebook - Account -> Hazem Mohamed - Group -> FOPCU 2026 - Dr/HZM ## Introduction & Alkanes Questions ### 1- Write True (T) for right sentence or False (F) for wrong sentence: | Answer | | |---|---| | F | The orders of increasing electro-negativity of the halogen atoms as follows: F > CI > I > Br | | T | All metals called electropositive elements | | T | The difference of EN between the atoms in non polar covalent bond equal zero | | | Examples of-l effect atoms and/or groups are F, CI, OH, NH,....etc | | | Mesomeric effect takes place in saturated systems | | | Carbanions are negatively charged species and Sp3 hybridized carbon | | T | Alkyl groups have +I effect | | | Inductive effect occurs via n bond orbital | | F | In non polar covalent bond the more electronegative atom acquires a partial negative charge S- | | T | Van der Waals forces responsible for holding uncharged molecules together in liquid or solid state | | T | Organic Chemistry is the study of carbon compounds that touches the lives of everyone | | T | EN is the ability of an atom to attract electrons | | F | Ionic bond formed between atoms with different in EN < 2 | | F | Electronegativity increases in the periodic table as we go down in the vertical column | | | The left column in the periodic table [group 1,2] called electronegative elements | | F | The difference of EN between the atoms in polar covalent bond equal zero | | | Examples of -I effect atoms are F, CI and alkyl groups | | | Inductive effect occurs through sigma bond | | | Nucleophiles are an electron loving species | | F | The order of the stability of carbanions as follows: : CH3 < RCH2 < R-CH < R-C: | | | Mesomeric effects may be transmitted in large conjugated molecules | | T | Free radical carbons are electrically neutral highly reactive species | | T | In polar covalent bond the more electronegative atom acquires a partial negative charge S- | | | Inductive effect depends on the EN of the atoms involved in the covalent bond | | | Electropositive elements have -I effect | | F | Nucleophiles attack the carbon of high electron density | | T | All halogens have -I effect | | | Mesomeric effect takes place in unsaturated molecules | | T | Nucleophiles attack the carbon with low electron density | | F | Carbocations are positively charged species and Sp3 hybridized carbon | | F | In Heterolytic cleavage, each atom involved in the covalent bond receives two electrons | | | Inductive effects are transmitted over only short distance (three atoms) | | | H-bond occurs between carbon atom and high electronegative atoms as F, O, N ...etc | | F | EN decreases in the periodic table from left to right | | T | Ionic bond formed between atoms widely different in EN > 2 | | F | EN is the ability of an atom to push electrons | | T | The order of stability of carbocations as follows; tert.carbocation > sec. Carbocation > primary carbocation | | F | The bond angle of Sp3 carbanion is 120 degree | | F | Free radical carbons are electrically neutral with low reactive species | | F | In Hemolytic cleavage, each atom involved in the covalent bond receives two electrons | | F | Inductive effect takes place in unsaturated molecules | | T | In polar covalent bond the lower electronegativety atom acquires partial positive charge S+ | | T | Carbocations are positively charged species and Sp2 hybridized carbon | | F | The bond angle of Sp2 carbocation carbon is 109.3 degree | | T | Electronegativety decreases" in the periodic table as we go down in the vertical column | | F | The difference of EN between the atoms in polar covalent bond >2 | ### 2-Give IUPAC name of the following: **Image of molecules** | Answer | | |---|---| | 3-ethyl 1,1-dimethyl cyclohexane | | | 1-bromo 3-ethyl cyclohexane | | | 3-cyclobutyl pentane | | | 1-cyclobutyl cyclopentane | | | methyl cyclobutane | | | 1-ethyl cyclopropane | | | 3,5,7-trimethyl nonane | | | 3-cyclobutyl-3-methyl heptane | | | 4-isopropyl-2,3-dimethyl nonane | | | 1,1-dimethyl-2-propyl cycloheptane | | | 1-isobutyl-3-methyl cyclohexane | | ### 3-The following are incorrect names, supply the proper name: | Answer | | |---|---| | 1,2- Dichloro cyclo-octane | 5,6-Dichloro cyclo-octane | | 1-Ethyl cyclopentane | 4-Ethyl cyclopentane | | 2,2,6-trimethyl octane | 2,2-Dimethyl-6-ethylheptane | | 3,4,4-trimethyl octane | 5,5,6-Trimethyloctane | | 2,3,5-trimethyl octane | 2-Isopropyl-4-methylheptane | | 2-chloro butane | 3-Chlorobutane | | 2-bromo-1-chloro propane | 1-Chloro-2-bromopropane | | cyclopropyl butane | n-Butylcycopropane | ### 4- Draw structures of the following: **Image of molecules** ### 5-Detect the type of Organic reaction in the following equation: | Answer | | |---|---| | Elemination (beta) | CH3CH(OH)CH₃ -H₂O CH3CH=CH2 | | Substition (Nu) | CH₂CH₂CH₂CI OH -HCI CH₂CH₂CH₂OH + CI | | Elemination (gamma) | CH₂CH₂CH₂CI | | Addition (E) | CH3CH=CH2 HCI CH₂CHCH, | | Addition (Nu) |CH3CH=O HCN CH3CHOH | | Substition (E) | **Image of molecules** | | Substition (free radical) | CH3 CH2 CH3 Cl2 hv, heat CH3-CH2-CH2CI + CH3-CH-CH3 | | Addition (Nu) | **Image of molecules** | ### 6- Arrange according to decreasing stability (رتب من الكبير إلى الصغير): **a) R3C, CH3, R2*CH, R*CH₂** **b) R3C, CH3, R-CH2, R2 CH** **c) CH3, R3C, R₂CH, R°CH₂** **Answer:** **a)** least stable is *CH₃- most stable is R₂C Order: R₂C* > R₂CH > R*CH2 > CH3 **b)** least stable is R3C- most stable is CH₂Order: CH3> R CH2> R₂CH>R3C **c)** The least stable is 'CH₃- most stable is R3C Order: R3C > R₂CH > R°CH2 > CH3 ### 7-Complete the following: **a) CH3CH=CH2 + H2 → Ni** **b) CH4 + Cl2 → ** **c) CH3-CH-CH3 + Br2 ROOR, U.V** **d) CH3Cl Li, CuI** **e) CH3-CH-CH3 + Cl2 ROOR, U.V** **f) CH4 + Br2 ROOR, U.V** **g) CH3-C-H Zn / Hg / HCI** **h) CH4 + 4Cl2 Light, U.V** ### 8-How can you synthesize the following using this methods: **a)** CH3CH2CH3** (Corey house synthesis)** **b)** CH3 CH2 CH3 **(Wolf - Kishner reduction)** **c)** CH3 CH2 CH2 CH3 **(Clemenson reduction)** ### Answer of Question (7): **a)** CH3 CH2 CH3 **b)** No reaction (Due to absence of reaction conditions "U.V & ROOR") **c)** Br CH3-C-CH3 CH3 **d)** CH3Li → CH3 Cu Li → No reaction (due to 2ry alkyl halide) **e)** CH3-C-CH3 and CH3-CH-CH2CI **f)** CH3Br **g)** C2H6 (CH3 CH3) **h)** CCl4 (chloroform) ### Answer of Question (8): **a)** **Image of molecules** **b)** CH3-C-CH3 NH2NH2 (hydrazine) CH3-C-CH3 Δ 0 **c)** CH3-C-CH2-CH3 Zn / Hg / HCI CH3 CH2 CH3 CH3 CH2 CH2 CH3