PCAT ochem nomenclature Questions
and Answers
Which prefixes count alphabetically? - correct answer-✅Di, tri, etc and tert- (t-), sec-, n-, don't count in
alphabetizing, but cyclo-, iso-, and neo- do
Carbonyl hydrates - correct answer-✅geminal diols, not commonly observed b/c they spontaneously
dehydrate
Ethers - correct answer-✅-ether function specified with alkoxy- prefix
-when numbering cyclic ethers (3-membered rings called oxiranes, epoxides), start with O then give
lowest #s for substituents
Aldehydes - correct answer-✅have suffix -al (but can also be -aldehyde), C in aldehyde is #1
Ketones - correct answer-✅have suffix -one, carbonyl group can have prefix oxo-, individual alkyl groups
can be listed in alphabetical order followed by the word ketone
*carbon atom adjacent to the carbonyl carbon can be alpha, next carbon beta, etc*
Carboxylic Acids - correct answer-✅-oic acid, terminal group and #1
Amines - correct answer-✅-amine, or prefix amino-
prefix N- indicates location of an additional alkyl group attached to the nitrogen
Thiol - correct answer-✅RSH, sulfhydrl- or -thiol
Imine - correct answer-✅R,RC=NR', imino- or -imine
Sulfide - correct answer-✅R,RS, alkylthio-
Azide - correct answer-✅RN3, azido-
Diazo - correct answer-✅RN2+, diazo-
and Answers
Which prefixes count alphabetically? - correct answer-✅Di, tri, etc and tert- (t-), sec-, n-, don't count in
alphabetizing, but cyclo-, iso-, and neo- do
Carbonyl hydrates - correct answer-✅geminal diols, not commonly observed b/c they spontaneously
dehydrate
Ethers - correct answer-✅-ether function specified with alkoxy- prefix
-when numbering cyclic ethers (3-membered rings called oxiranes, epoxides), start with O then give
lowest #s for substituents
Aldehydes - correct answer-✅have suffix -al (but can also be -aldehyde), C in aldehyde is #1
Ketones - correct answer-✅have suffix -one, carbonyl group can have prefix oxo-, individual alkyl groups
can be listed in alphabetical order followed by the word ketone
*carbon atom adjacent to the carbonyl carbon can be alpha, next carbon beta, etc*
Carboxylic Acids - correct answer-✅-oic acid, terminal group and #1
Amines - correct answer-✅-amine, or prefix amino-
prefix N- indicates location of an additional alkyl group attached to the nitrogen
Thiol - correct answer-✅RSH, sulfhydrl- or -thiol
Imine - correct answer-✅R,RC=NR', imino- or -imine
Sulfide - correct answer-✅R,RS, alkylthio-
Azide - correct answer-✅RN3, azido-
Diazo - correct answer-✅RN2+, diazo-
