Identification of primary, secondary and tertiary alcohols — NEET & JEE Questions

Question 1 · difficulty L1 · recall

In the Lucas test, tertiary alcohols generally react

• A. fastest, giving turbidity almost immediately
• B. only after prolonged heating
• C. not at all
• D. more slowly than primary alcohols

Question 2 · difficulty L2 · understanding

Lucas reagent is a mixture of concentrated HCl and

• A. anhydrous $ZnCl_2$
• B. $NaOH$
• C. $KMnO_4$
• D. $AgNO_3$

Question 3 · difficulty L2 · understanding

A primary alcohol on mild oxidation first generally gives

• A. an aldehyde
• B. a ketone
• C. an alkane
• D. a tertiary alcohol

Question 4 · difficulty L2 · understanding

A secondary alcohol on oxidation generally gives

• A. a ketone
• B. an aldehyde
• C. a carboxylic acid without C-C cleavage in one step
• D. no product at all

Question 5 · difficulty L3 · application

Which alcohol gives turbidity immediately at room temperature with Lucas reagent?

• A. Ethanol
• B. Propan-1-ol
• C. Propan-2-ol
• D. 2-Methylpropan-2-ol

Question 6 · difficulty L3 · application

Which alcohol is oxidised to propanone?

• A. Propan-1-ol
• B. Propan-2-ol
• C. 2-Methylpropan-2-ol
• D. Methanol

Question 7 · difficulty L3 · application

An alcohol is oxidised to ethanal under controlled conditions. Which alcohol was used?

• A. Methanol
• B. Ethanol
• C. Propan-1-ol
• D. Propan-2-ol

Question 8 · difficulty L3 · application

An alcohol resists ordinary oxidation because the carbon bearing $OH$ has no hydrogen. Which class is it most likely?

• A. Primary
• B. Secondary
• C. Tertiary
• D. Phenolic only

Question 9 · difficulty L4 · application

An unknown alcohol gives Lucas turbidity after a few minutes, not immediately, and oxidises to a ketone. What is it?

• A. Primary
• B. Secondary
• C. Tertiary
• D. Not an alcohol

Question 10 · difficulty L4 · application

An unknown alcohol gives no Lucas turbidity at room temperature but is readily oxidised to an aldehyde. Which class is indicated?

• A. Primary
• B. Secondary
• C. Tertiary
• D. Quaternary