Alkyl Halides

Alkyl Halides MDCAT MCQs with answers

37 past paper MCQs from Chemistry unit 15, Alkyl Halides, across 3 topics. They are arranged topic by topic; bigger topics show a sample here and link to their full set and to study notes. Tap “Show answer” for the correct option and a short solution.

Practise as a quiz

Nomenclature of Alkyl Halides

1.Neopentyl chloride belongs to which class of alkyl halides? (MDCAT 2022)

  1. primary alkyl halides
  2. secondary alkyl halides
  3. tertiary alkyl halides
  4. quaternary alkyl halides
Show answer

Correct answer: (a) primary alkyl halides

The carbon carrying the chlorine is attached to only one other carbon, so the halide is primary even though the molecule is branched.

2.IUPAC name of (CH3)3 CCH2 Br is (UHS MDCAT 2025)

  1. 1-bromopentane
  2. 1-bromo-2,2,2-trimethylethane
  3. 1-bromo-2,2-dimethylpropane
  4. 2-bromopentane
Show answer

Correct answer: (c) 1-bromo-2,2-dimethylpropane

The longest chain is propane, with two methyl groups on carbon 2 and the bromine on carbon 1.

3.IUPAC name of chloroform is: (SZABMU MDCAT 2025)

  1. methylchloride
  2. methyltrichloride
  3. trichloromethane
  4. chloromethane
Show answer

Correct answer: (c) trichloromethane

Chloroform is methane with three of its hydrogens replaced, that is trichloromethane.

All 9 Nomenclature of Alkyl Halides MCQs → Nomenclature of Alkyl Halides notes →

Structure and Reactivity of Alkyl Halides

4.Identify the correct ascending order of reactivity of alkyl halides: (MDCAT 2024)

  1. Cl, Br, I, F
  2. F, Cl, Br, I
  3. Br, I, F, Cl
  4. I, F, Cl, Br
Show answer

Correct answer: (b) F, Cl, Br, I

The weaker the carbon-halogen bond the better the leaving group, and that bond weakens from fluorine to iodine.

5.The order of reactivity of following R-X for SN reaction is: (SIBA MDCAT 2025)

  1. RF>RCl>RBr>RI
  2. RBr>RF>RCl>RI
  3. RCl>RF>RBr>RI
  4. RI>RBr>RCl>RF
Show answer

Correct answer: (d) RI>RBr>RCl>RF

The weakest carbon halogen bond breaks most readily, and that is the bond to iodine.

6.Reactivity of order of halogen acid is: (SZABMU MDCAT 2023)

  1. HF ˃ HCl ˃ HBr ˃ HI
  2. HBr ˃ HCl ˃ HI
  3. HCl ˃ HBr ˃ HI ˃ HF
  4. HI ˃ HBr ˃ HCl ˃ HF
Show answer

Correct answer: (d) HI ˃ HBr ˃ HCl ˃ HF

The weakest bond breaks first, and the bond to hydrogen is weakest in hydrogen iodide.

All 10 Structure and Reactivity of Alkyl Halides MCQs → Structure and Reactivity of Alkyl Halides notes →

Substitution versus Elimination

7.In $\mathrm{S_N1}$ reactions the correct order of reactivity of alkyl halides is: (MDCAT 2023)

  1. primary $>$ secondary $>$ tertiary
  2. tertiary $>$ secondary $>$ primary
  3. secondary $>$ tertiary $>$ primary
  4. tertiary $>$ primary $>$ secondary
Show answer

Correct answer: (b) tertiary $>$ secondary $>$ primary

The step that decides the rate is the formation of the carbocation, and a tertiary carbocation is the most stable.

8.Identify the correct statement related to substitution and elimination of alkyl halides: (MDCAT 2024)

  1. strong bases cause substitution in preference to elimination
  2. the role of leaving groups in elimination is similar to that in substitution
  3. substitution is favoured more than elimination by decreasing solvent polarity
  4. a decrease in temperature will favour elimination more than substitution
Show answer

Correct answer: (b) the role of leaving groups in elimination is similar to that in substitution

Both reactions need the halide to leave, so a better leaving group speeds up either one; strong bases and higher temperatures favour elimination.

9.Alkyl halides involving C-X bond breakage and C-Nu bond formation simultaneously would follow which one of the following mechanisms? (MDCAT 2024)

  1. $\mathrm{S_N1}$
  2. $\mathrm{S_N2}$
  3. E1
  4. E2
Show answer

Correct answer: (b) $\mathrm{S_N2}$

In $\mathrm{S_N2}$ the nucleophile attacks as the halide leaves, in one step through a single transition state.

All 18 Substitution versus Elimination MCQs → Substitution versus Elimination notes →

More MDCAT Chemistry units