OCR CHEMISTRY A PAPER H432 01 MARK
SCHEME SET 1 TEST BANK 2026 UPDATED
QUESTIONS WITH ANSWERS GRADED A+
⩥ sigma bond. Answer: the direct overlapping of two orbitals
⩥ pi bond. Answer: the sideways overlap of p orbitals
⩥ C=C how many pi bonds and sigma bonds are in this. Answer: one
sigma two pi bonds
⩥ what two types of isomers are found in alkenes. Answer: cis/trans and
E/Z
⩥ Difference between E/Z isomers and Cis/trans isomers. Answer: E/Z
compares relative position based in priority groups (IP rules) look at the
atomic number of the first bonded element
Cis/Trans compares the relative positions of identical groups
⩥ major and minor products in alkenes. Answer: the major product
forms the most stable carbocation intermediate during alkene reactions
tertiary>secondary>primary
,⩥ what type of polymer do alkenes produce?. Answer: addition
polymers
⩥ synthesis of an organic liquid. Answer: once reaction is complete into
a separating funnel. Neutralise any excess acid using sodium carbonate
(stops bubbling when all gone)
Allow 2 layers to settle
Use density into to establish layers. If density into not given, add water
to establish aqueous layer.
(aqueous layer get bigger)
Density of water is 1 anything greater is more dense.
collect the organic layer
add a drying agent to remove small traces of water left in the organic
layer (e.g.. anhydrous CaCl2)
If the question tells you the boiling point of the organic liquid say distil
dried product and collect fraction that comes over the boiling point.
⩥ 3 ways to determine purity of products. Answer: 1. boiling point
should match known data, boils over a narrow range
or
2. Run TLC, measure Rf value, compare to known data values/Run TLC
and compare to chromatogram of pure sample
or
,3. Run NMR/IR/Mass spectrum, compare to spectral database of pure
compounds.
⩥ How to purify by recrystallisation?. Answer: -dissolve in a minimum
volume of hot solvent
-cool in ice to recrystallise (impurities stay in solution)
-filter using Büchner flask/reduced pressure filtration
-wash with cold solvent
-dry
⩥ Does reflux have an open or closed system?. Answer: open
⩥ overall equation for ozone depletion. Answer: O3 + O -> 2O2
⩥ rate of formation of ozone =. Answer: rate of breakdown of ozone by
UV light =
⩥ what type of compound breaks down the ozone layer?. Answer:
chlorofluorocarbons
⩥ Initiation reaction of CCl3F
what is the mechanism, equation and why the radicals formed. Answer:
homolytic bond fission
, Cl. + CCl2F.
C-Cl bond broken as its weaker than C-F
⩥ Evidence for the structure of delocalised benzene against the kekule
structure. Answer: -Bond lengths of benzene are the same
-enthalpy of hydrogenation less exothermic than expected
-does not undergo addition reaction
⩥ why does benzene need a halogen carrier to undergo electrophilic
subsitution?. Answer: it is not electron dense enough to polarize the
molecule into an electrophile
⩥ electrophile. Answer: electron pair acceptor
⩥ what is the catalyst for halogenation of benzene?. Answer: AlX3
⩥ what is the catalyst for nitration of benzene?. Answer: sulfuric acid
⩥ How can you test for a phenol?. Answer: weak acid that reacts with
NaOH but too weak to react with Na2CO3 so no bubbles of CO2
⩥ why don't you need a catalyst for the halogenation and nitration of
phenol?. Answer: The lone pair on the oxygen molecule in the hydroxyl
group donates its pair of electrons into the delocalised pi ring. Increases
SCHEME SET 1 TEST BANK 2026 UPDATED
QUESTIONS WITH ANSWERS GRADED A+
⩥ sigma bond. Answer: the direct overlapping of two orbitals
⩥ pi bond. Answer: the sideways overlap of p orbitals
⩥ C=C how many pi bonds and sigma bonds are in this. Answer: one
sigma two pi bonds
⩥ what two types of isomers are found in alkenes. Answer: cis/trans and
E/Z
⩥ Difference between E/Z isomers and Cis/trans isomers. Answer: E/Z
compares relative position based in priority groups (IP rules) look at the
atomic number of the first bonded element
Cis/Trans compares the relative positions of identical groups
⩥ major and minor products in alkenes. Answer: the major product
forms the most stable carbocation intermediate during alkene reactions
tertiary>secondary>primary
,⩥ what type of polymer do alkenes produce?. Answer: addition
polymers
⩥ synthesis of an organic liquid. Answer: once reaction is complete into
a separating funnel. Neutralise any excess acid using sodium carbonate
(stops bubbling when all gone)
Allow 2 layers to settle
Use density into to establish layers. If density into not given, add water
to establish aqueous layer.
(aqueous layer get bigger)
Density of water is 1 anything greater is more dense.
collect the organic layer
add a drying agent to remove small traces of water left in the organic
layer (e.g.. anhydrous CaCl2)
If the question tells you the boiling point of the organic liquid say distil
dried product and collect fraction that comes over the boiling point.
⩥ 3 ways to determine purity of products. Answer: 1. boiling point
should match known data, boils over a narrow range
or
2. Run TLC, measure Rf value, compare to known data values/Run TLC
and compare to chromatogram of pure sample
or
,3. Run NMR/IR/Mass spectrum, compare to spectral database of pure
compounds.
⩥ How to purify by recrystallisation?. Answer: -dissolve in a minimum
volume of hot solvent
-cool in ice to recrystallise (impurities stay in solution)
-filter using Büchner flask/reduced pressure filtration
-wash with cold solvent
-dry
⩥ Does reflux have an open or closed system?. Answer: open
⩥ overall equation for ozone depletion. Answer: O3 + O -> 2O2
⩥ rate of formation of ozone =. Answer: rate of breakdown of ozone by
UV light =
⩥ what type of compound breaks down the ozone layer?. Answer:
chlorofluorocarbons
⩥ Initiation reaction of CCl3F
what is the mechanism, equation and why the radicals formed. Answer:
homolytic bond fission
, Cl. + CCl2F.
C-Cl bond broken as its weaker than C-F
⩥ Evidence for the structure of delocalised benzene against the kekule
structure. Answer: -Bond lengths of benzene are the same
-enthalpy of hydrogenation less exothermic than expected
-does not undergo addition reaction
⩥ why does benzene need a halogen carrier to undergo electrophilic
subsitution?. Answer: it is not electron dense enough to polarize the
molecule into an electrophile
⩥ electrophile. Answer: electron pair acceptor
⩥ what is the catalyst for halogenation of benzene?. Answer: AlX3
⩥ what is the catalyst for nitration of benzene?. Answer: sulfuric acid
⩥ How can you test for a phenol?. Answer: weak acid that reacts with
NaOH but too weak to react with Na2CO3 so no bubbles of CO2
⩥ why don't you need a catalyst for the halogenation and nitration of
phenol?. Answer: The lone pair on the oxygen molecule in the hydroxyl
group donates its pair of electrons into the delocalised pi ring. Increases
