smc-3676-08-Halogenated Organic Compounds

CHEMISTRY, M7 2024 HSC 12 MC

The structure of an organic substance is shown.

What is the preferred IUPAC name for this substance?

2-chloro-1-ethylbutanamide
2-chloro--ethylpropanamide
3-chloro--ethylbutanamide
3-chloro-1-ethylpropanamide

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Compound is a secondary amide.

→ Pre-fix (longest carbon chain) -butan

→ Suffix (functional group) -amide,

→ Alkyl chain bound to the amide nitrogen is treated as a substituent and as it is bound to the nitrogen atom -ethyl

→ As the amide group has the highest priority for the naming of the compound, carbon 1 is the carbon with the nitrogen and oxygen atom attached to it.

→ Hence, the chlorine atom is attached to carbon 3.

→ Compound name is 3-chloro--ethylbutanamide

CHEMISTRY, M7 2016 HSC 11 MC

What is the IUPAC name of the following compound?

1-bromo-1-chloro-2,2,2-trifluoroethane
1-chloro-1-bromo-2,2,2-trifluoroethane
2-chloro-2-bromo-1,1,1-trifluoroethane
2-bromo-2-chloro-1,1,1-trifluoroethane

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By Elimination:

→ Halogen substituents must be in alphabetical order (eliminate B and C)

→ Numbers are allocated using the first point of difference rule (eliminate A)

♦♦♦ Mean mark 28%.

CHEMISTRY, M7 2017 HSC 3 MC

What is the name of this compound?

2-chloro-1-fluorobutane
3-chloro-4-fluorobutane
1-fluoro-2-chlorobutane
4-fluoro-3-chlorobutane

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Compound: 2-chloro-1-fluorobutane

→ Functional groups are named alphabetically and hence -chloro precedes -fluoro.

CHEMISTRY, M7 2020 HSC 6 MC

The structure of a compound is shown.

What is the preferred IUPAC name of this compound?

1,1,1-tribromo-2-fluoropropan-3-ol
2-fluoro-3,3,3-tribromopropan-1-ol
2-fluoro-1,1,1-tribromopropan-3-ol
3,3,3-tribromo-2-fluoropropan-1-ol

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→ The hydroxyl functional group has the highest priority and therefore its associated is given the lowest possible number.

→ The substituents are named in alphabetical order.

♦ Mean mark 50%.

CHEMISTRY, M8 2020 HSC 5 MC

A spectrum is shown.

Which compound gives rise to this spectrum?

chloroethane
1-chloropropane
1, 2-dichloroethane
1, 2-dichloropropane

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→ The spectrum shows two signals, indicating 2 unique carbon environments.

→ Chloroethane is the only compound with 2 unique carbon environments.

CHEMISTRY, M7 2022 HSC 7 MC

The name 2-ethyl-3-chlorohexane does not follow IUPAC conventions.

What is the systematic name of this organic compound?

3-chloro-2-ethylhexane
4-chloro-3-methylheptane
4-chloro-5-ethylhexane
5-methyl-4-chloroheptane

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→ When drawn, the organic compound contains a carbon chain of 7 carbon atoms.

→ The methyl group should be numbered with the lower carbon number. Thus, the correct name IUPAC name is 4-chloro-3-methylheptane.

♦ Mean mark 43%.