Alcohol, phenol & ether MCQs for NEET — Chemistry Questions with Answers

(b) It contains >CHOH gp.

(d) Only CH₂OH gp. is oxidized to -COOH; Double bond is not affected.

(d) C₂H₅OH(Ethanol)$\stackrel{{\mathrm{PBr}}_3}{\to }$C₂H₅Br $\mathrm{\beta }$- elimination$\underset{-\mathrm{K} \mathrm{Br} -{\mathrm{H}}_2\mathrm{O} }{\overset{\mathrm{Alc}. \mathrm{KOH}}{\to }}$CH₂=CH₂$\stackrel{{\mathrm{H}}_2{\mathrm{SO}}_4}{\to }$CH₃-CH₂OSO₃H

$\underset{-{\mathrm{H}}_2{\mathrm{SO}}_4 }{\overset{{\mathrm{H}}_2\mathrm{O} /∆}{\to }}$${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}$

                   Ethanol

R-SH are thiols or mercaptans

(a) CH₃CH₂CH=CH₂$\underset{\mathrm{Anti}-\mathrm{Markownikoff}\text{'}\mathrm{s} \mathrm{rule}}{\overset{{\mathrm{HBr}}_2/{\mathrm{H}}_2{\mathrm{O}}_2}{\to }}$ CH₃CH₂CH₂CH₂Br$\to$ Bromo-butanane (1$°$ product)  CH₃CH₂CH₂CH₂Br$\underset{{\mathrm{S}}_{{\mathrm{N}}^2} \mathrm{reaction} ( \mathrm{Williamson}\text{'}\mathrm{s} \mathrm{synthesis})}{\overset{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{ONa}}{\to }}$CH₃CH₂CH₂CH₂OC₂H₅  

                                                                              Ethoxy - butane

(a) Salol is phenyl salicylate and is used as antiseptic

(b) C₂H₅COOC₂H₅$\stackrel{{\mathrm{LiAlH}}_4}{\to }$C₂H₅CH₂OH + C₂H₅OH

(c) Phenol is weak acid

Reactivity of H-atom of alcohol, (due to + IE of alkyl gp.)

Primary> Secondary> Tertiary

Also CH₃OH is more acidic than C₂H₅OH due to more +IE of -C₂H₅ gp.

The given reaction sequence phenol to X (by Zn dust), then X to Y (by anhydrous AlCl3 and CH3Cl), and finally Y to Z (by alkaline KMnO4) is the oxidation of a side chain. It converts a methyl group to a carboxyl group, so the final product Z is benzoic acid.