ECAT — Engineering College Admission Test (UET)

ECAT Chemistry — Organic Chemistry: Hydrocarbons to Carbonyls (Set 3)

Take the ECAT Chemistry — Organic Chemistry: Hydrocarbons to Carbonyls (Set 3): 30 multiple-choice questions (40 minutes) with instant scoring and a full…

What this test covers

30 ECAT Chemistry

Sample questions with answers

The first 5 questions of this test, with the correct answer and explanation.

Q1. The IUPAC name of CH₃CH(CH₃)CH₂CH(OH)CH₃ is:
- A. isohexanol
- B. 2-methylbutan-2-ol
- C. 2-methylpentan-4-ol
- D. 4-methylpentan-2-ol ✓
Answer: D. 4-methylpentan-2-ol
Explanation: Number from the end nearest the –OH: –OH on C2, methyl on C4 of a five-carbon chain.
Q2. The total number of alkene isomers (including cis–trans isomers, excluding cycloalkanes) of molecular formula C₄H₈ is:
- A. 4 ✓
- B. 5
- C. 3
- D. 2
Answer: A. 4
Explanation: But-1-ene, cis-but-2-ene, trans-but-2-ene and 2-methylpropene.
Q3. How many chiral carbon atoms (stereocentres) does butan-2-ol have?
- A. 2
- B. 0
- C. 3
- D. 1 ✓
Answer: D. 1
Explanation: Only C2 carries four different groups: –OH, –H, –CH₃ and –C₂H₅.
Q4. The number of structural isomers of C₄H₉Br is:
- A. 4 ✓
- B. 5
- C. 3
- D. 2
Answer: A. 4
Explanation: 1-bromobutane, 2-bromobutane, 1-bromo-2-methylpropane and 2-bromo-2-methylpropane.
Q5. What volume of oxygen is needed for the complete combustion of 10 mL of ethyne (C₂H₂) at constant T and P?
- A. 20 mL
- B. 50 mL
- C. 25 mL ✓
- D. 10 mL
Answer: C. 25 mL
Explanation: 2C₂H₂ + 5O₂ → 4CO₂ + 2H₂O: 10 × 5/2 = 25 mL.

The other 25 questions

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Q6. The mass of CO₂ produced by burning 4.4 g of propane (C₃H₈, 44 g/mol) completely is:
- A. 13.2 g
- B. 44 g
- C. 4.4 g
- D. 8.8 g
Q7. Treating a mixture of CH₃Br and C₂H₅Br with sodium in dry ether (Wurtz reaction) is expected to give:
- A. ethane and butane only
- B. only butane
- C. a mixture of ethane, propane and butane
- D. only propane
Q8. Dehydration of butan-2-ol with hot concentrated H₂SO₄ gives mainly:
- A. but-1-ene
- B. but-2-ene
- C. diethyl ether
- D. butan-2-one
Q9. Propene reacts with HBr in the presence of peroxides to give mainly:
- A. propan-1-ol
- B. 2-bromopropane
- C. 1,2-dibromopropane
- D. 1-bromopropane
Q10. The products of ozonolysis (followed by Zn/H₂O) of 2-methylpropene are:
- A. acetone and formaldehyde
- B. isobutyraldehyde
- C. two molecules of acetone
- D. acetaldehyde only
Q11. Hydration of ethyne in the presence of HgSO₄ and dilute H₂SO₄ yields:
- A. ethanol
- B. ethanoic acid
- C. propanone
- D. ethanal
Q12. Which of the following will give a white precipitate with ammoniacal silver nitrate?
- A. But-2-yne
- B. Butane
- C. But-1-yne
- D. But-1-ene
Q13. Propyne is treated first with sodamide (NaNH₂) and then with methyl iodide. The product is:
- A. propene
- B. but-2-yne
- C. but-1-yne
- D. 2-methylpropane
Q14. Which of the following is aromatic according to Hückel's rule?
- A. Benzene
- B. Cyclohexene
- C. Cyclooctatetraene
- D. Cyclobutadiene
Q15. The electrophile in the nitration of benzene using concentrated HNO₃ and concentrated H₂SO₄ is:
- A. NO₂⁺
- B. H₃O⁺
- C. NO⁺
- D. NO₃⁻
Q16. The major product of mononitration of toluene is a mixture of:
- A. 2,4,6-trinitrotoluene
- B. meta-nitrotoluene only
- C. benzyl nitrate
- D. ortho- and para-nitrotoluene
Q17. Which of the following undergoes electrophilic substitution most readily?
- A. Benzoic acid
- B. Nitrobenzene
- C. Benzene
- D. Phenol
Q18. Chlorobenzene is less reactive than benzene toward electrophilic substitution but gives ortho/para products. This is because chlorine:
- A. donates electrons by induction and withdraws by resonance
- B. is a meta director
- C. withdraws electrons by induction but donates by resonance
- D. has no effect on the ring
Q19. Which alkyl halide reacts fastest by the SN2 mechanism with the same nucleophile?
- A. (CH₃)₃CCH₂Br
- B. (CH₃)₃CBr
- C. CH₃CH₂Br
- D. (CH₃)₂CHBr
Q20. Hydrolysis of optically active 2-bromobutane by the SN1 mechanism gives mainly:
- A. only the inverted alcohol
- B. but-2-ene only
- C. a racemic mixture of butan-2-ol
- D. only the retained alcohol
Q21. Methylmagnesium bromide reacts with propanone and the product on acid hydrolysis is:
- A. 2-methylpropan-1-ol
- B. 2-methylpropan-2-ol
- C. propan-2-ol
- D. butan-2-ol
Q22. Which of the following is oxidised by acidified K₂Cr₂O₇ to a ketone?
- A. 2-methylpropan-2-ol
- B. Propan-1-ol
- C. Methanol
- D. Propan-2-ol
Q23. Which alcohol reacts first (turbid within seconds) with the Lucas reagent (ZnCl₂/HCl) at room temperature?
- A. ethanol
- B. butan-1-ol
- C. 2-methylpropan-2-ol
- D. butan-2-ol
Q24. The correct order of boiling points of propan-1-ol, propanal, methoxyethane and propane is:
- A. methoxyethane > propan-1-ol > propanal > propane
- B. propanal > propan-1-ol > methoxyethane > propane
- C. propane > methoxyethane > propanal > propan-1-ol
- D. propan-1-ol > propanal > methoxyethane > propane
Q25. 0.46 g of sodium reacts with excess ethanol. What volume of hydrogen at STP is released? (Na = 23)
- A. 22.4 mL
- B. 448 mL
- C. 112 mL
- D. 224 mL
Q26. Phenol reacts with bromine water to give:
- A. bromobenzene
- B. a yellow oil of p-bromophenol
- C. no reaction
- D. a white precipitate of 2,4,6-tribromophenol
Q27. Sodium ethoxide reacts with methyl iodide to give:
- A. methanol
- B. diethyl ether
- C. ethoxymethane (ethyl methyl ether)
- D. ethanol
Q28. Which of the following will NOT respond to the iodoform test?
- A. Propanone
- B. Ethanol
- C. Propan-1-ol
- D. Propan-2-ol
Q29. Fehling's solution is reduced by:
- A. propanone but not ethanal
- B. benzaldehyde
- C. both ethanal and propanone equally
- D. ethanal but not propanone
Q30. The reduction of ketones to alkanes using Zn–Hg and concentrated HCl is called:
- A. Cannizzaro reaction
- B. Wolff–Kishner reduction
- C. Clemmensen reduction
- D. Rosenmund reduction