CBSE 2026 · Region 3 · Set 1 · Q26 · 3 marks
Give reasons for the following :(a)Although chlorine is an electron-withdrawing group, yet it is ortho-, para-directing in electrophilic aromatic substitution reactions.(b)Aryl halides cannot be prepared by reacting phenol with concentrated halogen acids or phosphorus halides.(c)Chloroform is stored in closed dark coloured bottles.
Give reasons for the following :
(a)
Although chlorine is an electron-withdrawing group, yet it is ortho-, para-directing in electrophilic aromatic substitution reactions.
(b)
Aryl halides cannot be prepared by reacting phenol with concentrated halogen acids or phosphorus halides.
(c)
Chloroform is stored in closed dark coloured bottles.
Marking-scheme solution
(a)
Because +R effect of chlorine stabilises the intermediate carbocation and
hence activate the benzene ring at ortho and para positions.
(b)
Because the carbon – oxygen bond in phenols has a partial double bond
character and is difficult to break being stronger than single bond.
(c)
Because chloroform in the presence of air and light forms poisonous gas
phosgene.
Haloalkanes and HaloarenesPreparation of HaloarenesUnderstandshort_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 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.