AIIMS Chemistry Alcohols Phenols Ethers Class 12 Questions

The complete reaction is shown below. In the above reaction, the reactant undergoes 1,4 Michael addition first then the formed intermediate undergoes reduction in the presence of NaBH₄ to form the desired product.

Phenol reacts with CH₃I in presence of NaOH to form methoxybenzene as shown below: In the presence of NaOH, phenol forms phenoxide ion which is a better nucleophile than phenol. So, both assertion and reason are true and reason is the correct explanation of assertion.

$\text{C}_7\text{H}_{10}\text{O}$ reacts with $\text{CH}_3\text{MgBr}$ to give a compound $\text{C}_8\text{H}_{14}\text{O}$ which gives the test with iodoform, then find out structure of A

LiAlH₄/H₂O, NaBH₄/H₂O and Na/C₂H₅OH will reduce only −CHO, and not C≡C bond.

What is the major product P in the above reaction?

A primary alcohol with a vapour density of 29 contained C = 62.1%, H = 10.3% and reacted with bromine to give a derivative which contains C = 16.5%, H = 2.7% and Ba = 73.4%. The structural formula of the compound is

An allylide on hydrolysis gives allylene. The alkaline earth metal cation of the allylide dissolves in dry ether in the presence of an alkyl halide to form a Grignard reagent. The allylide is

In the following reaction, (A) and (B) are respectively, are

Assertion: Phenol is more acidic than ethanol. Reason: Phenoxide ion is resonance stabilized.

What is the major product P in the above reaction?

Assertion (A) A mixture of o-nitrophenol and p-nitrophenol can be separated by steam distillation. Reason (R) p-nitrophenol is steam volatile whereas o-nitrophenol is not steam volatile.

Which among the following compounds will give a secondary alcohol on reacting with Grignard reagent followed by acid hydrolysis? I. HCHO II. C₂H₅CHO III. CH₃COCH₃ IV. RCOOC₂H₅ Select the correct answer using the codes given below.

(i) CrO₃, (ii) Ac₂O/H⁺ → A; Product A is

Which of the following reaction will not produce ethylene glycol?

A compound containing two -OH groups attached with one carbon atom is unstable but which one of the following is stable?

Find the product for CH₃CH₂O⁻CH₂-CH₂O⁻CH₂-C₆H₅ + HI (excess)

Assertion : Rate of reaction of alkyl halide in Williamson's synthesis reaction is 1°RX > 2°RX > 3°RX. Reason : It is a type of molecular substitution reaction (Sₙ2).

Assertion : Dehydration of alcohols always takes place in basic medium. Reason : OH⁻ is a better leaving group.

The major product of the following reaction is

²⁻phenylethylbromide when heated with NaOEt, elimination takes place. No deuterium exchange takes place when the reaction is carried out in C₂H₅OD solvent. The mechanism will be

Assertion : Ethers can be dried by using sodium wire. Reason : Ethers do not react with sodium.

Assertion : C₂H₅Br reacts with alcoholic solution of AgNO₂ to form nitroethane as the major product. Reason : NO₂⁻ is an ambident ion.

CH₃OC₂H₅ and (CH₃)₃C – OCH₃ are treated with concentrated acidic iodide. The fragments after reactions obtained are

Propene on hydroboration and oxidation produces

CH₃CH=CH₂ on mercuration and demercuration produces

Assertion : Benzene diazonium salt on boiling with water forms phenol. Reason : C—N bond is polar.

The major product formed in the following reaction is $\text{CH}_3 - \overset{\text{CH}_3}{\underset{\text{H}}{\text{C}}} - \text{CH}_2\text{Br} \xrightarrow[\text{CH}_3\text{OH}]{\text{CH}_3\text{O}^-}$

Assertion : t-Butyl methyl ether is not prepared by the reaction of t-butyl bromide with sodium methoxide. Reason : Sodium methoxide is a strong nucleophile.

The most suitable reagent for the conversion of RCH₂OH → RCHO is

Assertion : Isobutanol does not give iodoform test. Reason : It does not have α-hydrogen.

Assertion :²⁻bromobutane on reaction with sodium ethoxide in ethanol gives¹⁻butene as a major product. Reason :¹⁻butene is more stable than²⁻butene.

Assertion : The major products formed by heating C₆H₅CH₂OCH₃ with HI are C₆H₅CH₃I and CH₃OH. Reason : Benzyl cation is more stable than methyl cation.

Assertion : Alcohols are dehydrated to hydrocarbons in the presence of acidic zeolites. Reason : Zeolites are porous catalysts.

Propan^{-1}-ol can be prepared from propene by

Lucas test is used for the determination of

The reaction: C₂H₅OH + SOCl₂ → C₂H₅Cl + SO₂ + HCl is known as

Assertion : Phenol is a weak acid than ethanol. Reason : Groups with +M effect and –I effect decrease acidity at m-position.

Assertion : Ethers behave as bases in the presence of mineral acids. Reason : It is due to the presence of lone pair of electrons on the oxygen.

Which of the following statements is not true about alcohols?

Assertion (A) : o-nitrophenol is more volatile than p-nitrophenol. Reason (R) : Intramolecular hydrogen bonding is present in o-nitrophenol while intermolecular H⁻bonding is in p-nitrophenol.

Assertion (A) : CH₃OCH₃ and C₂H₅OH has comparable molecular weight but boiling point of C₂H₅OH is more than dimethyl ether. Reason (R) : C₂H₅OH forms intermolecular H⁻bonding while CH₃OCH₃ forms intramolecular H⁻bonding.

Assertion (A) : CHCl₃ and CH₃OH are miscible. Reason (R) : One of them is polar.