A Data Booklet may be used.
Menthone is a component in mint oil.
Which statements about menthone are correct?
Source: 2022 HCI J1 Promo P1 Q16
CommonWhich molecule is not optically active?
Source: 2022 HCI J1 Promo P1 Q17
TPI is an enzyme that is essential for energy production. It catalyses the following reaction.
—TPI→
What type of reaction is the overall process?
Source: 2024 CJC J2 Prelim P1 Q19
3,4-dimethylhexane, , exists as three different types of molecule. Molecule X rotates plane polarised light to the right. Molecule Y rotates plane polarised light to the left. Molecule Z has no effect on plane polarised light.
Source: 2024 DHS J2 Prelim P3 Q2(b)(iv) and (v)
Source: 2024 DHS J2 Prelim P3 Q2(c)(i)
Source: 2024 VJC J2 Prelim P3 Q3(a)(iii)
CommonName each of the following reactions as addition, elimination or substitution.
Source: EJC 2022 JC1 Introduction to Organic Chemistry Tutorial, Q5
Source: RJC H2 Chemistry Tutorial 10 (Introduction to Organic Chemistry), Q6(e)
Source: 2025 EJC J2 Prelim P2 Q5(b)(i)
Source: 2024 VJC J2 Prelim P3 Q5(b)(iv)
Source: EJC 2022 JC1 Introduction to Organic Chemistry Tutorial, Q9
A1 and 2 only[1]
C[1]
Molecules that are optically active contain chiral centre(s) and have non-superimposable mirror images. These 4 molecules contain chiral centres, but the presence of chiral centres does not always mean that the molecule has a non-superimposable mirror image and hence is optically active. The presence of an internal plane of symmetry will mean that the molecule is identical (superimposable) to its mirror image and is optically inactive.
C has 2 chiral centres, but an internal plane of symmetry is present. Its mirror image is superimposable on itself, so it is optically inactive (an achiral compound, also known as a meso compound).
Aisomerisation[1]
The molecular formula of both the reactant and the product is RC2H3O2. Therefore both molecules are isomers of each other, with the same molecular formula.
Options B and C only describe the reactions of ketones and primary alcohols separately, and not the overall process. Option D is not true, as no small inorganic molecule is lost here.
[1]
Molecule Z has an internal plane of symmetry and is thus an achiral molecule, which is optically inactive.[1]
The C atom in CO2 has its 2s orbital mixed with one of its three 2p orbitals to form two degenerate sp hybrid orbitals.[1]
The bond angle is 120° and the shape is trigonal planar around each C (or the hexagonal ring is planar).[1]
Each carbon atom is sp2 hybridised and uses two of its three sp2 hybrid orbitals to overlap head-on with the sp2 hybrid orbitals of the adjacent carbon atoms to form C–C σ bonds.[1]
Each carbon atom has an unhybridised 2p orbital that overlaps sideways with the adjacent two 2p orbitals to form π bonds. This results in delocalised electrons in the π system.[1]
C6H5CH(OH)CH=CH2: optical isomerism[1]
| [1]
There are two lone pairs of electrons on the oxygen atom of the water molecule, which enable it to attack electron-deficient sites to form new covalent bonds.[1]
CH2ClCH2CO2H is the stronger acid, as Cl exerts an electron-withdrawing inductive effect that helps to disperse the negative charge of the anion formed when the acid dissociates in water.[1]
X, CH3CH(OH)C3H7:
|
| [1]
Constitutional isomerism and enantiomerism[1]
Y, CH3CH=CHC2H5: [1]
Cis-trans isomerism[1]