Alcohols, Phenols & Ethers

Assertion (A): The Br₂/H₂O test distinguishes phenol from cyclohexanol (both cyclic, 6-membered-ring, -OH compounds). Reason (R): Phenol's ring is aromatic (sp$^2$ carbons, activated by -OH resonance) $\rightarrow$ EAS…

Two samples tested with Br₂/H₂O (added dropwise): Sample X: immediate decolourisation + white precipitate forms Sample Y: Br₂ colour persists, no precipitate Most consistent identification:

Which of the following alcohols give a POSITIVE iodoform test? Select ALL correct. (A) Ethanol (CH₃CH₂OH) (B) Propan-2-ol [CH₃CH(OH)CH₃] (C) Methanol (CH₃OH) (D) Propan-1-ol (CH₃CH₂CH₂OH)

Ethanol treated with I₂ + NaOH (iodoform reagent) and gently warmed. The characteristic positive result is:

Assertion (A): The Na metal test alone cannot distinguish alcohol from phenol (both positive), but does distinguish either from an ether (negative). Reason (R): Both alcohols and phenols have acidic O-H bonds reactive…

Three samples treated with dry sodium metal: Sample A: vigorous effervescence (H₂ gas) Sample B: vigorous effervescence (H₂ gas) Sample C: no visible reaction Sample C most likely belongs to which class?

Assertion (A): The Lucas test is most reliable for C₄-C₆ alcohols but less practical for methanol/ethanol. Reason (R): The test relies on the alkyl chloride product being insoluble (causing visible turbidity); methyl…

Three C₄H₁₀O alcohol samples treated with Lucas reagent (ZnCl₂/conc. HCl): Sample 1: immediate turbidity at RT Sample 2: turbidity after ~5-10 min warming Sample 3: no turbidity after 30+ min Correct classification:

Assertion (A): Salicylic acid (2-hydroxybenzoic acid) gives a positive (violet) FeCl₃ test, even though it also contains -COOH. Reason (R): Salicylic acid retains a free phenolic -OH group; the FeCl₃ test detects this…

Neutral aqueous FeCl₃ is added to an unknown compound dissolved in water. An intense violet/purple colour develops immediately. This confirms the compound is most likely:

Assertion (A): Countries mandating ethanol-blended petrol require ANHYDROUS (water-free) ethanol, not the ~95% azeotropic ethanol from simple distillation. Reason (R): Even small amounts of water in the ethanol-petrol…

'Power alcohol' = ethanol used as a fuel additive/blend with petrol. Which statement correctly describes a key advantage of ethanol-blended petrol?