CBSE 2025 · Region 2 · Set 1 · Q21 · 2 marks
(a)In the following pair of halogen compounds, which compound undergoes $\displaystyle \mathrm{S}_{\mathrm{N}} 1$ reaction faster and why ? 
(b) Arrange the following compounds in increasing order of their reactivity towards $\displaystyle \mathrm{S}_{\mathrm{N}} 2$ displacement : $\displaystyle 2$-Bromo-$\displaystyle 2$-methylbutane, $\displaystyle 1$-Bromopentane, $\displaystyle 2$-Bromopentane.
(a)
In the following pair of halogen compounds, which compound undergoes $\displaystyle \mathrm{S}_{\mathrm{N}} 1$ reaction faster and why ? (b) Arrange the following compounds in increasing order of their reactivity towards $\displaystyle \mathrm{S}_{\mathrm{N}} 2$ displacement : $\displaystyle 2$-Bromo-$\displaystyle 2$-methylbutane, $\displaystyle 1$-Bromopentane, $\displaystyle 2$-Bromopentane.
(b) Arrange the following compounds in increasing order of their reactivity towards $\displaystyle \mathrm{S}_{\mathrm{N}} 2$ displacement : $\displaystyle 2$-Bromo-$\displaystyle 2$-methylbutane, $\displaystyle 1$-Bromopentane, $\displaystyle 2$-Bromopentane.Marking-scheme solution
(a)
, due to the formation of more stable tertiary carbocation.
(b)
$\displaystyle 2$-Bromo-$\displaystyle 2$-methylbutane < $\displaystyle 2$-Bromopentane < $\displaystyle 1$-Bromopentane.
Haloalkanes and HaloarenesChemical Reactions of Haloalkanes and HaloarenesUnderstandvery_short_answermedium
More from Haloalkanes and Haloarenes
- Reaction of 1-phenyl-2-chloropropane with alcoholic KOH gives mainly:2023 · asked 3×
- An alkyl halide of molecular formula C 6 H 13 Cl on treatment with alcoholic KOH gives two isomeric alkenes…2023 · asked 3×
- Assertion: The boiling points of alkyl halides decrease in the order RI RBr RCl RF. Reason (R): The van der…2025 · asked 3×
- Define the following: 2+1=3 (i) Enantiomers (ii) Racemic mixture Why is chlorobenzene resistant to…2025 · asked 3×
- Assertion: n-Butyl chloride has higher boiling point than n-Butyl bromide. Reason (R): C - Cl bond is more…2025 · asked 3×
- Write any two differences between S N 1 and S N 2 reactions. Which of the following compounds would undergo S…2025 · asked 3×
- Account for the following: Benzyl chloride is highly reactive towards S N 1 reaction. (±)-Butan-2-ol is…2023 · asked 3×
- A compound with molecular formula C 4 H 9 I which is a primary alkyl halide, reacts with alcoholic KOH to…2025 · asked 3×
CBSE Class 12 Chemistry past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.