Which of the following is Lindlar catalyst?
Hydrocarbons · Class 11 · JEE Main Previous Year Question
Which of the following is Lindlar catalyst?
- a✓
Partially deactivated palladised charcoal
- b
Cold dilute solution of
- c
Zinc chloride and
- d
Sodium and Liquid
Partially deactivated palladised charcoal
Step 1: Definition of Lindlar Catalyst
Lindlar catalyst = Pd deposited on (or charcoal), poisoned with lead acetate and quinoline. This partial deactivation prevents over-reduction.
Alkyne + Lindlar cis-alkene (stops at alkene stage).
Step 2: Identify Options
- (a) Partially deactivated palladised charcoal: matches Lindlar. CORRECT
- (b) Cold dil. : Baeyer reagent for dihydroxylation
- (c) /HCl: Lucas reagent for alcohol identification
- (d) Na/Liquid : dissolving metal reduction (gives trans-alkene)
Key Points:
- Lindlar: Pd (poisoned) gives syn/cis addition of to alkyne
- Na/liq gives trans-alkene (anti addition)
- These two reagents are opposites: Lindlar = cis; Na/liq = trans
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