1
SUMMER 2026
PREDICTED PAPER
A Level Chemistry B (Salters)
H433/03 Practical skills in chemistry
Practical Insert
Time allowed: 1 hour 30 minutes
OCR
INSTRUCTIONS
• Do not send this Insert for marking; it should be retained in the centre or recycled.
INFORMATION
• This document consists of 4 pages. Any blank pages are indicated
for more: tyrionpapers.com
, 2
Identifying Unknown Organic Compounds
A group of students carries out a series of tests to identify unknown organic compounds.
They record their observations and use these to determine the structure and functional
groups present in each compound.
Reagents available:
• Bromine water (aqueous bromine)
• Aqueous silver nitrate (AgNO₃) solution
• Ethanol
• Water bath at 60°C
Experiment 1: Test for unsaturation
The student tests four organic liquids (A, B, C and D) with bromine water. In each case, 10
drops of bromine water are added to 1 drop of the unknown compound. The mixtures are
shaken and the observations recorded.
Table 1
Compound Observation Identification
Remains orange/brown; two layers form
A Cyclohexane (alkane — no
reaction)
Decolourises immediately — turns
B colourless Cyclohexene (alkene — addition
reaction)
Remains orange; one layer
C Heptane (alkane — no reaction)
Decolourises rapidly — turns colourless
D Limonene (contains C=C double
bond)
for more: tyrionpapers.com
SUMMER 2026
PREDICTED PAPER
A Level Chemistry B (Salters)
H433/03 Practical skills in chemistry
Practical Insert
Time allowed: 1 hour 30 minutes
OCR
INSTRUCTIONS
• Do not send this Insert for marking; it should be retained in the centre or recycled.
INFORMATION
• This document consists of 4 pages. Any blank pages are indicated
for more: tyrionpapers.com
, 2
Identifying Unknown Organic Compounds
A group of students carries out a series of tests to identify unknown organic compounds.
They record their observations and use these to determine the structure and functional
groups present in each compound.
Reagents available:
• Bromine water (aqueous bromine)
• Aqueous silver nitrate (AgNO₃) solution
• Ethanol
• Water bath at 60°C
Experiment 1: Test for unsaturation
The student tests four organic liquids (A, B, C and D) with bromine water. In each case, 10
drops of bromine water are added to 1 drop of the unknown compound. The mixtures are
shaken and the observations recorded.
Table 1
Compound Observation Identification
Remains orange/brown; two layers form
A Cyclohexane (alkane — no
reaction)
Decolourises immediately — turns
B colourless Cyclohexene (alkene — addition
reaction)
Remains orange; one layer
C Heptane (alkane — no reaction)
Decolourises rapidly — turns colourless
D Limonene (contains C=C double
bond)
for more: tyrionpapers.com
