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question_answer1) Direction (1 - 30): In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices. Assertion: Addition reaction of water to but-1-ene in acidic medium yields butan-1-ol. Reason: Addition of water in acidic medium proceeds through the formation of secondary carbocation.
question_answer2) Assertion: p-nitrophenol is more acidic than phenol. Reason: Nitro group helps in the stabilisation of the phenoxide ion by dispersal of negative charge due to resonance.
question_answer3) Assertion: Bond angle in ethers is slightly less than the tetrahedral angle. Reason: There is a repulsion between the two bulky (-R) groups.
question_answer4) Assertion: Boiling points of alcohols are higher than ethers. Reason: They can form intennolecular hydrogen bonding.
question_answer5) Assertion: Like bromination of benzene, bromination of phenol is also carried out in the presence of Lewis acid. Reason: Lewis acid polarises the bromine molecule.
question_answer6) Assertion: o-Nitrophenol is less soluble in water than the m- and p-isomers. Reason: m- and p-Nitrophenols exist as associated molecules.
question_answer7) Assertion: Ethanol is a weaker acid than phenol. Reason: Sodium ethoxide may be prepared by the reaction of ethanol with aqueous NaOH.
question_answer8) Assertion: Phenols give \[{{o}^{-}}\] and p-nitrophenol on nitration with conc. \[HN{{O}_{3}}\] and \[{{H}_{2}}S{{O}_{4}}\]mixture. Reason: -OH group in phenol is \[{{o}^{-}}\], p- directing.
question_answer9) Assertion: Ethers have specific dipole moment values Reason: The C - O bond is of polar nature.
question_answer10) Assertion: With HI, anisole forms phenol and methyl iodide. Reason: \[{{I}^{-}}\]ion will combine with smaller group to avoid steric hindrance.
question_answer11) Assertion: Ethers behave as bases in the presence of mineral acids. Reason: Due to the presence of lone electron pair on the oxygen atom.
question_answer12) Assertion: \[{{\left( C{{H}_{3}} \right)}_{3}}COH\] when heated with conc. \[{{H}_{2}}S{{O}_{4}}\] gives isobutylene as the main product and not di-tertiary butyl ether. Reason: All alcohols are readily dehydrated with conc. \[{{H}_{2}}S{{O}_{4}}\]
question_answer13) Assertion: Tert-butyl methyl ether on cleavage with HI at 373 K gives tert-butyl iodide and methanol. Reason: The reaction occurs by \[{{S}_{N}}^{2}\] mechanism.
question_answer14) Assertion: 2-Bromobutane on reacting with sodium ethoxide in ethanol gives but-1-ene as the major product. Reason: But-2-ene is more stable than but-1-ene.
question_answer15) Assertion: The major products formed by heating \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}OC{{H}_{3}}\] with HI are \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}I\] and \[C{{H}_{3}}OH\]. Reason: Benzyl cation is more stable than methyl cation.
question_answer16) Assertion: Cleavage of anisole with HI at 373 K gives phenol and \[C{{H}_{3}}I\] Reason: Due to resonance, \[O-{{C}_{6}}{{H}_{5}}\] bond is stronger than \[O-C{{H}_{3}}\] bond.
question_answer17) Assertion: Phenol is more reactive than benzene towards electrophilic substitution reaction. Reason: In case of phenol, the intermediate carbocation is resonance stabilised.
question_answer18) Assertion: Phenol is more acidic than ethanol. Reason: Phenoxide ion is resonance stabilised.
question_answer19) Assertion: Phenol forms 2, 4, 6 - tribromophenol on treatment with \[B{{r}_{2}}\] water at 273 K. Reason: Phenol is ortho and para directing in nature.
question_answer20) Assertion: Reason: Alkyl aryl ethers on reaction with halogen acids always form aryl halide due to formation of more stable carbocation.
question_answer21) Assertion: Order of reactivity of alcohols involving cleavage of O-H bond is; primary > secondary > tertiary. Reason: This is due to + I effect of the alkyl group (R).
question_answer22) Assertion: p-Nitrophenol is a stronger acid than p-cresol. Reason: \[N{{O}_{2}}\] group is an electron withdrawing group while \[C{{H}_{3}}\] group is electron releasing in nature.
question_answer23) Assertion: o-Nitrophenol and p-Nitrophenol are separated by steam distillation. Reason: o-Nitrophenol has intramolecular H-bonding while molecules of p-Nitrophenol are linked by intermolecular H-bonding.
question_answer24) Assertion: Phenol is more reactive than benzene towards electrophilic substitution. Reason: OH group in phenol is ortho and para directing in nature.
question_answer25) Assertion: 2-bromobutane on reacting with sodium ethoxide in ethanol gives but-2-ene as the major product. Reason: But-2-ene is more stable than but-1-ene.
question_answer26) Assertion: Change in colour of acidic solution of potassium dichromate by breath test is used to test drunk drivers. Reason: Change in colour is to do the complexation of alcohol with potassium dichromate.
question_answer27) Assertion: Phenol undergoes Kolbe's reaction whereas ethanol does not. Reason: Phenoxide ion is more basic than ethoxide ion.
question_answer28) Assertion: \[{{C}_{2}}{{H}_{5}}OH\] is a weaker base than \[{{C}_{6}}{{H}_{5}}OH\] but is a stronger nucleophile than phenol. Reason: In \[{{C}_{6}}{{H}_{5}}OH\], the lone electron pair on oxygen is withdrawn towards the ring due to resonance.
question_answer29) Assertion: Picric acid is a strong acid inspite of the absence of the carboxyl group. Reason: The three -\[N{{O}_{2}}\] groups in picric acid activate the phenate ion.
question_answer30) Assertion: Phenol reacts with \[C{{H}_{3}}I\] in the presence of NaOH to form methoxy benzene. Reason: Phenoxide ion is a better nucleophile than phenol.
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