Alcohols, Phenols and Ethers — Important Questions

CH₃CH(OH)CH₃, CH₃CH(OH)CH₂CH₃

Secondary alcohols have the OH group attached to a carbon atom that is bonded to two other carbon atoms. CH₃CH(OH)CH₃ (propan-2-ol) and CH₃CH(OH)CH₂CH₃ (butan-2-ol) are both secondary alcohols. The others are primary or tertiary alcohols.

Hydrolysis of diazonium salts, Fusion of chlorobenzene with NaOH, Cumene process

Phenols can be prepared by: (1) hydrolysis of diazonium salts with water, (2) fusion of haloarenes like chlorobenzene with NaOH at high temperature and pressure, and (3) the cumene process involving oxidation of cumene. The other options are methods for preparing alcohols, not phenols.

Ethene

When ethanol is heated with concentrated H₂SO₄ at 443 K (170°C), dehydration occurs to form ethene (CH₂=CH₂) and water. At lower temperatures (413 K), diethyl ether would be formed instead. The high temperature favors elimination over substitution.

Primary, secondary and tertiary alcohols

Lucas test uses concentrated HCl and ZnCl₂ to distinguish between primary, secondary, and tertiary alcohols based on the rate of formation of alkyl halides. Tertiary alcohols react immediately (turbidity appears), secondary alcohols react within 5 minutes, and primary alcohols do not react at room temperature.