Grade 12 : Chemistry - Alcohols (Set 1)

Question 1

Which of the following compounds gives immediate turbidity at room temperature when treated with Lucas reagent (anhydrous $ ext{ZnCl}_2$+ conc.$ ext{HCl}$)?

Accepted Answer

B) 2-Methylpropan-2-ol

Answer

A) Butan-1-ol

Answer

C) Butan-2-ol

Answer

D) Propan-1-ol

Question 2

The hydroboration-oxidation of propene with diborane followed by alkaline $ ext{H}_2 ext{O}_2$ yields which major product?

Accepted Answer

C) Propan-1-ol

Answer

A) Propan-2-ol

Answer

B) Propanoic acid

Answer

D) Propane-1,2-diol

Question 3

What is the correct order of decreasing acidity among the following alcohols: methanol (I), ethanol (II), propan-2-ol (III), and 2-methylpropan-2-ol (IV)?

Accepted Answer

A) I > II > III > IV

Answer

B) IV > III > II > I

Answer

C) II > I > III > IV

Answer

D) I > III > II > IV

Question 4

Heating ethanol with excess concentrated $ ext{H}_2 ext{SO}_4$at443 K ($170^\circ ext{C}$) leads primarily to the formation of:

Accepted Answer

B) Ethene

Answer

A) Diethyl ether

Answer

C) Ethyl hydrogen sulphate

Answer

D) Ethanal

Question 5

When vapours of secondary butyl alcohol (butan-2-ol) are passed over heated copper at 573 K, the major organic product obtained is:

Accepted Answer

C) Butan-2-one

Answer

A) Butanal

Answer

B) But-2-ene

Answer

D) 2-Methylpropene

Question 6

Which reagent is most suitable for converting a primary alcohol into an aldehyde without over-oxidation to a carboxylic acid?

Accepted Answer

D) Pyridinium chlorochromate (PCC)

Answer

A) Acidified$	ext{KMnO}_4$

Answer

B) Alkaline $	ext{K}_2	ext{Cr}_2	ext{O}_7$

Answer

C) Concentrated $	ext{HNO}_3$

Question 7

The reaction of methyl magnesium bromide ($ ext{CH}_3 ext{MgBr}$) with methanal (formaldehyde) followed by acidic hydrolysis gives:

Accepted Answer

A) Ethanol

Answer

B) Methanol

Answer

C) Propan-2-ol

Answer

D) Acetone

Question 8

Which of the following compounds will give a positive iodoform test upon treatment with $ ext{I}_2$and aqueous$ ext{NaOH}$?

Accepted Answer

B) Ethanol

Answer

A) Methanol

Answer

C) Propan-1-ol

Answer

D) Pentan-3-ol

Question 9

What is the correct order of reactivity of alcohols towards esterification with acetic acid?

Accepted Answer

D) $	ext{CH}_3	ext{OH} > 1^\circ > 2^\circ > 3^\circ$

Answer

A) $3^\circ > 2^\circ > 1^\circ > 	ext{CH}_3	ext{OH}$

Answer

B) $2^\circ > 1^\circ > 3^\circ > 	ext{CH}_3	ext{OH}$

Answer

C) $1^\circ > 3^\circ > 2^\circ > 	ext{CH}_3	ext{OH}$

Question 10

Alcohols have significantly higher boiling points than isomeric ethers and haloalkanes of comparable molecular mass because of:

Accepted Answer

C) Intermolecular hydrogen bonding

Answer

A) Higher dipole moment

Answer

B) Dipole-dipole interactions

Answer

D) Intramolecular hydrogen bonding

Question 11

In the Victor Meyer test, a primary alcohol produces a blood-red colouration. What compound is responsible for this characteristic colour?

Accepted Answer

A) Sodium salt of nitrolic acid

Answer

B) Pseudonitrol

Answer

C) Alkyl nitrite

Answer

D) Nitroalkane

Question 12

When 2-methylbutan-2-ol undergoes acid-catalysed dehydration, the major alkene obtained according to Zaitsev's rule is:

Accepted Answer

B) 2-Methylbut-2-ene

Answer

A) 2-Methylbut-1-ene

Answer

C) 3-Methylbut-1-ene

Answer

D) Pent-2-ene

Question 13

The reaction of an alcohol with thionyl chloride ($ ext{SOCl}_2$) in the presence of pyridine yields an alkyl chloride. Why is this method preferred for preparing alkyl halides?

Accepted Answer

C) The by-products ($	ext{SO}_2$and$	ext{HCl}$) are gases and escape easily

Answer

A) It is an explosive reaction

Answer

B) It requires no heating

Answer

D) It gives a mixture of stereoisomers

Question 14

Which product is formed when acetone (propanone) is treated with ethylmagnesium bromide followed by protonation with water?

Accepted Answer

A) 2-Methylbutan-2-ol

Answer

B) Pentan-2-ol

Answer

C) Pentan-3-ol

Answer

D) 2-Methylbutan-1-ol

Question 15

Which of the following statements about the solubility of lower alcohols in water is correct?

Accepted Answer

D) They are completely miscible with water due to intermolecular hydrogen bonding

Answer

A) They are insoluble due to high covalent character

Answer

B) They dissolve only in non-polar organic solvents

Answer

C) Their solubility increases monotonically as the alkyl chain lengthens

Question 16

Commercial alcohol is made unfit for drinking by the addition of small amounts of methanol and pyridine. This product is called:

Accepted Answer

B) Denatured alcohol (methylated spirit)

Answer

A) Absolute alcohol

Answer

C) Rectified spirit

Answer

D) Power alcohol

Question 17

Acid-catalysed hydration of 3,3-dimethylbut-1-ene gives which major product due to carbocation rearrangement?

Accepted Answer

A) 2,3-Dimethylbutan-2-ol

Answer

B) 3,3-Dimethylbutan-2-ol

Answer

C) 3,3-Dimethylbutan-1-ol

Answer

D) 2,3-Dimethylbutan-1-ol

Question 18

What is the correct IUPAC name of the compound commonly known as glycerol?

Accepted Answer

C) Propane-1,2,3-triol

Answer

A) Propane-1,2-diol

Answer

B) Propane-1,3-diol

Answer

D) 2-Hydroxypropane-1,3-diol

Question 19

Passing tertiary butyl alcohol vapours over hot metallic copper at 573 Kgives primarily:

Accepted Answer

D) 2-Methylpropene

Answer

A) 2-Methylpropanal

Answer

B) Butan-2-one

Answer

C) Propanone and carbon dioxide

Question 20

The reaction of an alcohol with metallic sodium evolves which gas?

Accepted Answer

B) Hydrogen ($	ext{H}_2$)

Answer

A) Oxygen ($	ext{O}_2$)

Answer

C) Methane ($	ext{CH}_4$)

Answer

D) Carbon monoxide ($	ext{CO}$)

Set 1Grade 12 : Chemistry - Alcohols