Alcohols - preparation, properties and dehydration — NEET & JEE Questions

Question 1 · difficulty L1 · recall

The functional group of an alcohol is

• A. hydroxyl, -OH
• B. carbonyl, >C=O
• C. carboxyl, -COOH
• D. amino, -NH2

Question 2 · difficulty L2 · understanding

The denticity of the ligand present in the Fehling's reagent is ___________.

Question 3 · difficulty L2 · understanding

A hydroxy compound $(\mathrm{X})$ with molar mass $122 \mathrm{~g} \mathrm{~mol}^{-1}$ is acetylated with acetic anhydride, using a large excess of the reagent ensuring complete acetylation of all hydroxyl groups. The product obtained has a molar mass of $290 \mathrm{~g} \mathrm{~mol}^{-1}$. The number of hydroxyl groups present in compound $(\mathrm{X})$ is:

• A. 2
• B. 4
• C. 3
• D. 5

Question 4 · difficulty L2 · understanding

Given below are two statements : Statement (I) : The boiling points of alcohols and phenols increase with increase in the number of C -atoms. Statement (II) : The boiling points of alcohols and phenols are higher in comparison to other class of compounds such as ethers, haloalkanes. In the light of the above statements, choose the correct answer from the options given below :

• A. Statement I is false but Statement II is true
• B. Both Statement I and Statement II are true
• C. Statement I is true but Statement II is false
• D. Both Statement I and Statement II are false

Question 5 · difficulty L2 · understanding

Incorrect method of preparation for alcohols from the following is:

• A. Hydroboration-oxidation of alkene.
• B. Reaction of Ketone with $$\mathrm{RMgBr}$$ followed by hydrolysis.
• C. Ozonolysis of alkene.
• D. Reaction of alkyl halide with aqueous $$\mathrm{NaOH}$$.

Question 6 · difficulty L2 · understanding

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Butan -1- ol has higher boiling point than ethoxyethane. Reason R: Extensive hydrogen bonding leads to stronger association of molecules. In the light of the above statements, choose the correct answer from the options given below:

• A. A is false but R is true
• B. Both A and R are true but R is not the correct explanation of A
• C. Both A and R are true and R is the correct explanation of A
• D. A is true but R is false

Question 7 · difficulty L2 · understanding

The water gas on reacting with cobalt as a catalyst forms

• A. Methanoic acid
• B. Methanol
• C. Methanal
• D. Ethanol

Question 8 · difficulty L2 · understanding

A solution of $$\mathrm{Cr O_5}$$ in amyl alcohol has a __________ colour.

• A. Yellow
• B. Orange-Red
• C. Green
• D. Blue

Question 9 · difficulty L2 · understanding

When ethanol is heated with conc. $$\mathrm{H}_{2} \mathrm{SO}_{4}$$, a gas is produced. The compound formed, when this gas is treated with cold dilute aqueous solution of Baeyer's reagent, is

• A. formaldehyde
• B. formic acid
• C. glycol
• D. ethanoic acid

Question 10 · difficulty L2 · understanding

Given below are two statements : Statement I : On heating with $$\mathrm{KHSO}_{4}$$, glycerol is dehydrated and acrolein is formed. Statement II : Acrolein has fruity odour and can be used to test glycerol's presence. Choose the correct option.

• A. Both Statement I and Statement II are correct.
• B. Both Statement I and Statement II are incorrect.
• C. Statement I is correct but Statement II is incorrect.
• D. Statement I is incorrect but Statement II is correct.