NUMS — Medical & Dental Entry Test

NUMS Chemistry — Inorganic and Organic Chemistry (Set 7)

Take the NUMS Chemistry — Inorganic and Organic Chemistry (Set 7): 30 multiple-choice questions (40 minutes) with instant scoring and a full answer…

What this test covers

• 30 NUMS Chemistry

Sample questions with answers

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

1. Q1. How many structural isomers are possible for dichloropropane, C₃H₆Cl₂ (stereoisomers are not counted separately)?

   • A. 4 ✓
   • B. 6
   • C. 5
   • D. 3

   Answer: A. 4

   Explanation: The two Cl atoms can be placed on C1,C1 (1,1-), C1,C2 (1,2-), C1,C3 (1,3-) or C2,C2 (2,2-): four structural isomers.

2. Q2. What is the IUPAC name of CH₃CH₂CH(CH₃)CH₂CH₂OH?

   • A. 3-Ethylbutan-1-ol
   • B. 3-Methylpentan-1-ol ✓
   • C. 3-Methylpentan-5-ol
   • D. 2-Ethylbutan-1-ol

   Answer: B. 3-Methylpentan-1-ol

   Explanation: The longest chain carrying –OH has 5 carbons; –OH gets locant 1, so the methyl group is on C3: 3-methylpentan-1-ol.

3. Q3. Ozonolysis of 2-methylbut-2-ene followed by reductive work-up (Zn/H₂O) gives which products?

   • A. Propanone and ethanal ✓
   • B. Propanone and propanal
   • C. Ethanal and 2-methylpropanal
   • D. Butanone and methanal

   Answer: A. Propanone and ethanal

   Explanation: (CH₃)₂C=CHCH₃ is cleaved at the double bond: (CH₃)₂C=O (propanone) from the disubstituted carbon and CH₃CHO (ethanal) from the other.

4. Q4. Which alcohol is NOT oxidised by warm acidified potassium dichromate(VI) under normal conditions?

   • A. Butan-1-ol
   • B. 2-Methylpropan-2-ol ✓
   • C. Propan-2-ol
   • D. Butan-2-ol

   Answer: B. 2-Methylpropan-2-ol

   Explanation: A tertiary alcohol has no hydrogen on the carbon bearing –OH, so it resists oxidation without breaking C–C bonds. Primary alcohols give aldehydes/acids, secondary alcohols give ketones.

5. Q5. In the Lucas test (anhydrous ZnCl₂ in concentrated HCl) at room temperature, which alcohol gives a turbidity most quickly?

   • A. Butan-1-ol
   • B. 2-Methylpropan-2-ol ✓
   • C. Propan-2-ol
   • D. Butan-2-ol

   Answer: B. 2-Methylpropan-2-ol

   Explanation: Reaction proceeds through a carbocation; the tertiary cation from 2-methylpropan-2-ol is most stable, so the insoluble chloride appears immediately.

The other 25 questions

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6. Q6. What is the major product when benzoic acid is nitrated with a mixture of concentrated nitric and sulphuric acids?

   • A. 3-Nitrobenzoic acid
   • B. 2,4-Dinitrobenzoic acid
   • C. 4-Nitrobenzoic acid
   • D. 2-Nitrobenzoic acid

7. Q7. What volume of hydrogen at STP (22.4 dm³ mol⁻¹) is released when 2.3 g of sodium reacts completely with excess water? (Na = 23)

   • A. 0.56 dm³
   • B. 2.24 dm³
   • C. 11.2 dm³
   • D. 1.12 dm³

8. Q8. Which aldehyde does NOT give a red precipitate of copper(I) oxide when warmed with Fehling's solution?

   • A. Ethanal
   • B. Butanal
   • C. Benzaldehyde
   • D. Propanal

9. Q9. Which compound gives a yellow precipitate of iodoform (CHI₃) on warming with iodine and sodium hydroxide?

   • A. Butanal
   • B. Butan-2-one
   • C. Propanal
   • D. Pentan-3-one

10. Q10. Which aldehyde cannot undergo aldol condensation in dilute alkali?

    • A. Butanal
    • B. Propanal
    • C. Ethanal
    • D. 2,2-Dimethylpropanal

11. Q11. Which compound is the strongest base in aqueous solution?

    • A. Ammonia
    • B. Aniline
    • C. Methylamine
    • D. Acetamide

12. Q12. Which compound gives the carbylamine reaction (a foul-smelling isocyanide on heating with chloroform and alcoholic KOH)?

    • A. Ethylamine
    • B. N,N-Dimethylaniline
    • C. Diethylamine
    • D. Triethylamine

13. Q13. Which of the following sugars does NOT reduce Fehling's solution?

    • A. Glucose
    • B. Maltose
    • C. Fructose
    • D. Sucrose

14. Q14. Glycine, alanine and serine are each used exactly once to build a tripeptide. How many different tripeptides can be formed?

    • A. 27
    • B. 6
    • C. 3
    • D. 9

15. Q15. Which of the following is a condensation polymer?

    • A. Polythene
    • B. Terylene (a polyester)
    • C. Polyvinyl chloride
    • D. Teflon

16. Q16. Aqueous copper(II) sulphate is pale blue, but it turns deep blue on adding excess ammonia. What is the best explanation?

    • A. Sulphate is displaced and the Cu²⁺ ion is reduced to Cu⁺
    • B. Copper is oxidised from the +2 state to the +3 state
    • C. NH₃ donates electrons and raises the number of d electrons
    • D. NH₃ ligands replace H₂O and alter the d-orbital splitting

17. Q17. Excess aqueous silver nitrate is added to a solution of [Co(NH₃)₅Cl]Cl₂. How many moles of AgCl precipitate per mole of the complex?

    • A. 1
    • B. 2
    • C. 0
    • D. 3

18. Q18. What is the IUPAC name of K₄[Fe(CN)₆]?

    • A. Tetrapotassium cyanoferrate(II)
    • B. Potassium hexacyanoferrate(II)
    • C. Potassium hexacyanoiron(II)
    • D. Potassium hexacyanoferrate(III)

19. Q19. Which Group 2 carbonate decomposes at the lowest temperature on heating?

    • A. BaCO₃
    • B. SrCO₃
    • C. MgCO₃
    • D. CaCO₃

20. Q20. Chlorine is passed into hot, concentrated sodium hydroxide solution. Which pair of chlorine-containing products forms?

    • A. NaCl and NaClO₃
    • B. NaCl and NaClO₄
    • C. NaCl and NaClO
    • D. NaClO and NaClO₃

21. Q21. Sulphur dioxide decolourises acidified potassium permanganate solution. What does this show about SO₂?

    • A. It acts as a bleaching agent by removing hydrogen
    • B. It acts as an oxidising agent, being reduced to sulphur
    • C. It acts as a reducing agent, being oxidised to sulphate
    • D. It acts as an acid by neutralising permanganate

22. Q22. Copper turnings are added to dilute nitric acid (about 6 mol dm⁻³). Which gas is evolved, and what happens to it in air?

    • A. Hydrogen, which burns with a pop
    • B. Nitrogen dioxide, which is colourless in air
    • C. Dinitrogen oxide, which turns brown in air
    • D. Nitrogen monoxide, which turns brown as it forms NO₂

23. Q23. A sample of water contains 3.24 g of calcium hydrogencarbonate, Ca(HCO₃)₂. Temporary hardness is removed by boiling: Ca(HCO₃)₂ → CaCO₃ + H₂O + CO₂. What mass of CaCO₃ is precipitated? (Ca = 40, C = 12, O = 16, H = 1)

    • A. 2.00 g
    • B. 3.24 g
    • C. 1.00 g
    • D. 1.62 g

24. Q24. In the Solvay process, why does sodium hydrogencarbonate precipitate from the ammoniacal brine saturated with CO₂?

    • A. The heat released by the reaction forces it to crystallise out
    • B. It is insoluble in every aqueous solution at any temperature
    • C. It reacts with the ammonium chloride that is present to form a gas
    • D. It is the least soluble salt present in the cold mixture

25. Q25. How many different monochloro structural isomers can form when 2-methylbutane undergoes free-radical chlorination?

    • A. 4
    • B. 2
    • C. 5
    • D. 3

26. Q26. Pent-3-en-2-ol, CH₃–CH(OH)–CH=CH–CH₃, has how many stereoisomers in total?

    • A. 2
    • B. 8
    • C. 4
    • D. 3

27. Q27. Propyne and but-2-yne are both colourless gases at room temperature. Which test distinguishes them?

    • A. But-2-yne gives a white precipitate with ammoniacal silver nitrate
    • B. Propyne does not react with sodium metal
    • C. Propyne gives a white precipitate with ammoniacal silver nitrate
    • D. But-2-yne decolourises bromine water but propyne does not

28. Q28. Butan-2-ol is heated with concentrated sulphuric acid. Which is the major alkene formed, according to Saytzeff's rule?

    • A. But-1-ene
    • B. But-2-ene
    • C. 2-Methylpropene
    • D. Butane

29. Q29. Benzoic acid and phenol are separately shaken with aqueous sodium hydrogencarbonate. What is observed?

    • A. Phenol effervesces but benzoic acid does not
    • B. Benzoic acid effervesces but phenol does not
    • C. Both effervesce equally
    • D. Neither effervesces

30. Q30. Which alkali metal burns in excess oxygen to form the normal oxide (M₂O) as its main product?

    • A. Sodium
    • B. Potassium
    • C. Lithium
    • D. Rubidium