Purpose: Self-check IUPAC nomenclature, functional groups, organic reactions, and isomerism.
Q1
IUPAC name for: \( \text{CH}_3\text{-CH(CH}_3\text{)-CH}_2\text{-CH}_2\text{-CH}_3 \)
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Longest chain = 5 → pentane. Number from end giving lowest locant for methyl branch: 2-methylpentane.
Q2
Name (cis isomer): \( \text{CH}_3\text{CH=CHCH}_2\text{CH}_3 \)
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5-C alkene; double bond C2-C3 → cis-2-pentene (or (Z)-pent-2-ene).
Q3
Draw a structural isomer of pent-1-yne (C₅H₈) with the triple bond in a different position.
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pent-2-yne: CH₃–C≡C–CH₂–CH₃.
Q4
Functional group in \( \text{CH}_3\text{CH}_2\text{COOCH}_3 \)?
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Ester (R-COO-R'): methyl propanoate.
Q5
IUPAC name for \( \text{CH}_3\text{CH}_2\text{CH(OH)CH}_3 \).
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Butan-2-ol (secondary alcohol).
Q6
Classify: (a) 2-methylpropan-2-ol, (b) butan-1-ol, (c) pentan-3-ol.
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(a) Tertiary, (b) Primary, (c) Secondary.
Q7
Predict: \( \text{CH}_2\text{=CH}_2 + \text{HBr} \rightarrow \) ?
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Electrophilic addition → bromoethane, CH₃CH₂Br.
Q8
Major Markovnikov product for propene + HCl?
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2-chloropropane — Cl adds to more substituted C.
Q9
Equation for esterification of ethanoic acid with methanol (H⁺ cat.).
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$$\text{CH}_3\text{COOH} + \text{CH}_3\text{OH} \xrightarrow{\text{H}^+} \text{CH}_3\text{COOCH}_3 + \text{H}_2\text{O}$$ Methyl ethanoate.
Q10
Balance complete combustion of butane.
Show solution
$$2\,\text{C}_4\text{H}_{10} + 13\,\text{O}_2 \rightarrow 8\,\text{CO}_2 + 10\,\text{H}_2\text{O}$$
Q11
How many structural isomers of \( \text{C}_5\text{H}_{12} \)?
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Three: n-pentane, 2-methylbutane, 2,2-dimethylpropane.
Q12
Does 2-methylpropan-2-ol have a chiral centre?
Show solution
No — central C has three identical CH₃ substituents.