Which of the following IUPAC names are NOT correct?
Which of the following IUPAC names are NOT correct?
The correct options are
B Pent-3-ene
C 4-Pentanol
D 3-Chloropropane
Let us attempt to write the corresponding structures.
For (a) word root = Eth
It is a di-oic-acid
Hence
Correctly named as well
For (b) word root = pent which means 5 carbon atoms.
The primary suffix 'ene' indicates unsaturation
So pent-3-ene refers to
CH3−CH2−H|C=H|C−CH3
Or
CH3−CH2−CH=CH−CH3
But its name should be 2-pentene as the right numbering gives the lowest number to the carbon atoms containing the double bond.
Ans (b)
similarly for 4-pentanol
word root = pent
primary suffix = ane
secondary suffix = al
Thus the structure is
CH3−CH2−CH2−OH|CH−CH3
As in (b) the numbering is wrong. Correct name should have been 2-Pentanol or Pentan-2-ol
Ans (c)
For (d), 3-Chloropropane ,word root = prop
primary suffix = ane
secondary suffix = 3-chloro
corresponding structure would be CH3−CH2−CH2−Cl.
Again this IUPAC name is wrong due to wrong numbering it should be 1-chloropropane.
Ans (d)
(b), (c),& (d) would be the answer.
B
Pent-3-ene
C
4-Pentanol
D
3-Chloropropane
Let us attempt to write the corresponding structures.
For (a) word root = Eth
It is a di-oic-acid
Hence
Correctly named as well
For (b) word root = pent which means 5 carbon atoms.
The primary suffix 'ene' indicates unsaturation
So pent-3-ene refers to
CH3−CH2−H|C=H|C−CH3
Or
CH3−CH2−CH=CH−CH3
But its name should be 2-pentene as the right numbering gives the lowest number to the carbon atoms containing the double bond.
Ans (b)
similarly for 4-pentanol
word root = pent
primary suffix = ane
secondary suffix = al
Thus the structure is
CH3−CH2−CH2−OH|CH−CH3
As in (b) the numbering is wrong. Correct name should have been 2-Pentanol or Pentan-2-ol
Ans (c)
For (d), 3-Chloropropane ,word root = prop
primary suffix = ane
secondary suffix = 3-chloro
corresponding structure would be CH3−CH2−CH2−Cl.
Again this IUPAC name is wrong due to wrong numbering it should be 1-chloropropane.
Ans (d)
(b), (c),& (d) would be the answer.
