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CHEMISTRY, M7 2024 HSC 12 MC

The structure of an organic substance is shown.
 

   

What is the preferred IUPAC name for this substance?

  1. 2-chloro-1-ethylbutanamide
  2. 2-chloro-\(N\)-ethylpropanamide
  3. 3-chloro-\(N\)-ethylbutanamide
  4. 3-chloro-1-ethylpropanamide
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\(C\)

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Compound is a secondary amide.

→ Pre-fix (longest carbon chain) \(\Rightarrow\) -butan

→ Suffix (functional group) \(\Rightarrow\) -amide, 

→ Alkyl chain bound to the amide nitrogen is treated as a substituent and as it is bound to the nitrogen atom \(\Rightarrow\) \(N\)-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-\(N\)-ethylbutanamide

\(\Rightarrow C\)

CHEMISTRY, M7 2016 HSC 11 MC

What is the IUPAC name of the following compound?
 

  1. 1-bromo-1-chloro-2,2,2-trifluoroethane
  2. 1-chloro-1-bromo-2,2,2-trifluoroethane
  3. 2-chloro-2-bromo-1,1,1-trifluoroethane
  4. 2-bromo-2-chloro-1,1,1-trifluoroethane
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`D`

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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)

`=>D`


♦♦♦ Mean mark 28%.

CHEMISTRY, M7 2020 HSC 6 MC

The structure of a compound is shown.
 


 

What is the preferred IUPAC name of this compound?

  1. 1,1,1-tribromo-2-fluoropropan-3-ol
  2. 2-fluoro-3,3,3-tribromopropan-1-ol
  3. 2-fluoro-1,1,1-tribromopropan-3-ol
  4. 3,3,3-tribromo-2-fluoropropan-1-ol
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`D`

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→ The hydroxyl functional group has the highest priority and therefore its associated `text{C}` is given the lowest possible number.

→ The substituents are named in alphabetical order.

`=> D`


♦ Mean mark 50%.

CHEMISTRY, M8 2020 HSC 5 MC

A \( \ce{^13C NMR} \) spectrum is shown.
 


 

Which compound gives rise to this spectrum?

  1. chloroethane
  2. 1-chloropropane
  3. 1, 2-dichloroethane
  4. 1, 2-dichloropropane
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`A`

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→ The \( \ce{^13C NMR} \) spectrum shows two signals, indicating 2 unique carbon environments.

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

`=> A`

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?

  1. 3-chloro-2-ethylhexane
  2. 4-chloro-3-methylheptane
  3. 4-chloro-5-ethylhexane
  4. 5-methyl-4-chloroheptane
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`B`

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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.

`=> B`


♦ Mean mark 43%.