Which of the following compounds is classified as a secondary alcohol?

• A. ${\mathrm{CH}}_3\mathrm{CH}\mathrm{OH}$ (ethanol)
• B. ${\mathrm{CH}}_3\mathrm{CH}\mathrm{OH}{\mathrm{CH}}_3$ (2-propanol)
• C. ${\mathrm{CH}}_3\mathrm{CH}{\mathrm{CH}}_2\mathrm{OH}$ (1-propanol)
• D. ${\mathrm{CH}}_3\mathrm{OH}$ (methanol)

Answer: (B)

Verified step by step guidance

1. Recall the definition of primary, secondary, and tertiary alcohols based on the carbon atom bonded to the hydroxyl (-OH) group: a primary alcohol has the -OH attached to a carbon bonded to only one other carbon, a secondary alcohol has the -OH attached to a carbon bonded to two other carbons, and a tertiary alcohol has the -OH attached to a carbon bonded to three other carbons.
2. Identify the carbon atom that carries the hydroxyl (-OH) group in each compound and count how many carbon atoms are directly attached to it.
3. For ethanol (CH\_3CH\_2OH), the -OH is attached to a carbon bonded to only one other carbon, so it is a primary alcohol.
4. For 2-propanol (CH\_3CHOHCH\_3), the -OH is attached to the middle carbon, which is bonded to two other carbons, making it a secondary alcohol.
5. For 1-propanol (CH\_3CH\_2CH\_2OH) and methanol (CH\_3OH), the -OH is attached to a carbon bonded to only one or no other carbons, so both are primary alcohols.