Introduction to Organic Chemistry
6 marks · NormalDraw the displayed formula for propene.
Give the IUPAC name for the compound with the following displayed formula.
State and explain the difference in bonding between the compounds you answered in parts a and b.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) — · must show Three-carbon chain, Double bond between C1 and C2, Correct number of hydrogens: CH2=CH–CH3
(b) propan-2-ol
(c) — · must show Propene has a C=C double bond (alkene), Propan-2-ol has an –OH group (alcohol), Propene: unsaturated, Propan-2-ol: saturated
Show mark scheme and worked solution
Marking points
D1 (a) · 1 mark · Correct 3-carbon backbone with double bond between first two carbons
D2 (a) · 1 mark · Correct number of hydrogens to match propene (CH2=CH–CH3)
N1 (b) · 2 marks · Correct IUPAC name: propan-2-ol (accept alternative formats such as 2-propanol)
E1 (c) · 1 mark · States the key difference: propene has a C=C double bond; propan-2-ol has an –OH group
E2 (c) · 1 mark · Explains how this affects classification/properties (alkene vs alcohol, or saturation)
Worked solution
(a) Propene has 3 carbon atoms with one double bond between carbon 1 and carbon 2. Its displayed formula is:
or shown as:
(b) The given displayed formula is CH3–CH(OH)–CH3. This follows the structure of propan-2-ol, which is an alcohol with the –OH group on the second carbon. The IUPAC name is propan-2-ol.
(c) Propene contains a carbon–carbon double bond, which makes it an alkene and unsaturated. Propan-2-ol contains a hydroxyl (–OH) group on the central carbon and only single bonds between carbons (alkane chain), making it a saturated alcohol. The key difference is propene’s double bond vs. propan-2-ol’s –OH group.