2,2-dimethyl-1-pentanol, 2-methyl-2-pentanol and 2-methyl-3-pentanol are:
A. Primary alcohol, secondary alcohol and tertiary alcohol, respectively
B. Secondary alcohol, primary alcohol and tertiary alcohol, respectively
C. Tertiary alcohol, secondary alcohol and primary alcohol, respectively
D. Primary alcohol, tertiary alcohol and secondary alcohol, respectively
Answer (2)
2,2-dimethyl-1-pentanol is a primary alcohol.
2-methyl-2-pentanol is a tertiary alcohol.
2-methyl-3-pentanol is a secondary alcohol.
The answer is D: Primary alcohol, tertiary alcohol and secondary alcohol, respectively. D
Explanation
Understanding the Problem We need to classify three alcohols: 2,2-dimethyl-1-pentanol, 2-methyl-2-pentanol, and 2-methyl-3-pentanol as primary, secondary, or tertiary alcohols. The classification depends on the number of carbon atoms bonded to the carbon atom that is directly bonded to the -OH group.
Classifying the Alcohols
2,2-dimethyl-1-pentanol: The -OH group is attached to carbon number 1. Carbon number 1 is bonded to two hydrogen atoms and one carbon atom (carbon number 2). Therefore, it is a primary alcohol.
2-methyl-2-pentanol: The -OH group is attached to carbon number 2. Carbon number 2 is bonded to one methyl group, one ethyl group (carbon 3), and the -OH group. Therefore, it is a tertiary alcohol.
2-methyl-3-pentanol: The -OH group is attached to carbon number 3. Carbon number 3 is bonded to one hydrogen atom, one methyl group (carbon 2), and one propyl group (carbon 4). Therefore, it is a secondary alcohol.
Final Answer Based on the classifications, 2,2-dimethyl-1-pentanol is a primary alcohol, 2-methyl-2-pentanol is a tertiary alcohol, and 2-methyl-3-pentanol is a secondary alcohol. Therefore, the correct option is D.
Examples
Understanding the classification of alcohols is crucial in organic chemistry as it affects their reactivity and the types of reactions they undergo. For example, primary alcohols can be oxidized to aldehydes and carboxylic acids, while secondary alcohols are oxidized to ketones. Tertiary alcohols are generally resistant to oxidation. Knowing whether an alcohol is primary, secondary, or tertiary helps predict its behavior in chemical reactions and is essential in designing and synthesizing organic compounds.
The classifications for the given alcohols are: 2,2-dimethyl-1-pentanol is a primary alcohol, 2-methyl-2-pentanol is a tertiary alcohol, and 2-methyl-3-pentanol is a secondary alcohol. Therefore, the correct option is D.
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