NEET (UG)

Practice Test 1 — Haloalkanes and Haloarenes

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct & Statement-based)

Question 1

The reagent that gives the purest alkyl chloride from an alcohol is:

Solution: $\text{SOCl}_2$: gaseous by-products escape.

Question 2

An SN2 reaction is fastest for a:

Solution: Least steric hindrance favours backside attack.

Question 3

The stereochemical result of an SN1 reaction at a chiral carbon is:

Solution: Planar carbocation is attacked from both faces.

Question 4

Statements: (I) Haloarenes resist nucleophilic substitution. (II) The C–X bond in haloarenes has partial double-bond character. Which is/are correct?

Solution: Both correct; (II) is a reason for (I).

Question 5

The Finkelstein reaction is used to prepare an alkyl:

Solution: NaI/dry acetone gives the iodide.

Question 6

The major product of dehydrohalogenation follows:

Solution: Saytzeff: more substituted, more stable alkene.

Question 7

A Grignard reagent is destroyed by:

Solution: Water gives the alkane; keep everything dry.

Question 8

Which compound depletes the ozone layer?

Solution: CFCs release Cl radicals that destroy ozone.

Section B — Assertion & Reason

Question 9

A: SN2 reactions proceed with inversion of configuration.
R: The nucleophile attacks the carbon from the side opposite the leaving group.

Solution: Backside (opposite-side) attack is exactly why inversion occurs — R explains A.

Question 10

A: Chlorobenzene is less reactive than chloroethane towards nucleophiles.
R: The C–Cl bond in chlorobenzene has partial double-bond character due to resonance.

Solution: Resonance strengthens the C–Cl bond, lowering reactivity — R explains A.

Question 11

A: Tertiary halides react predominantly by the SN1 mechanism.
R: Tertiary carbocations are more stable than primary ones.

Solution: Greater carbocation stability speeds the rate-determining ionisation — R explains A.

Question 12

A: Chloroform is stored in dark coloured bottles filled to the brim.
R: Chloroform is highly flammable and explodes in light.

Solution: A is true, but the real reason is aerial oxidation to phosgene, not flammability — so R is false.