A-level
CHEMISTRY
Paper 2 Organic and Physical Chemistry
Monday 8 June 2025 Afternoon Time allowed: 2 hours
Materials
For this paper you must have: For Examiner’s Use
• the Periodic Table/Data Booklet, provided as an insert (enclosed)
• a ruler with millimetre measurements Question Mark
• a scientific calculator, which you are expected to use where appropriate.
1
Instructions 2
• Use black ink or black ball-point pen.
• Fill in the boxes at the top of this page. 3
• Answer all questions.
4
• You must answer the questions in the spaces provided. Do not write outside the
box around each page or on blank pages. 5
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). 6
• All working must be shown.
7
• Do all rough work in this book. Cross through any work you do not want to be
marked. 8
9
Information
• The marks for questions are shown in brackets. TOTAL
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
• The maximum mark for this paper is 105.
, lOMoAR cPSD| 56342273
2
Do not write
outside the
box
*JUN207405201*
IB/M/Jun20/E11 7405/2
Answer all questions in the spaces provided.
This question is about rates of reaction.
0 1
Phosphinate ions (H2PO2–) react with hydroxide ions to produce hydrogen gas as
shown.
H2PO2– + OH− → HPO32– + H2
A student completed an experiment to determine the initial rate of this reaction. The
student used a solution containing phosphinate ions and measured the volume of
hydrogen gas collected every 20 seconds at a constant temperature. Figure 1
shows a graph of the student’s results.
Figure 1
IB/M/Jun20/7405/2
, lOMoAR cPSD| 56342273
3
Do not write
outside the
box
0 1
Use the graph in Figure 1 to determine the initial rate of reaction for this experiment.
.1
State its units. Show your working on the graph.
[3 marks]
Rate Units
*02*
Turn over ►
IB/M/Jun20/7405/2
, lOMoAR cPSD| 56342273
4
Do not write
outside the
box
Another student reacted different initial concentrations of phosphinate ions with an
0 1 .2 excess of hydroxide ions. The student measured the time (t) taken to collect 15
cm3 of hydrogen gas. Each experiment was carried out at the same temperature.
Table 1 shows the results.
Table 1
Initial [H2PO2–] / mol dm–3 t/s
0.25 64
0.35 32
0.50 16
1.00 4
State the relationship between the initial concentration of phosphinate and time (t).
Deduce the order of the reaction with respect to phosphinate.
[2 marks]
Relationship
Order
Question 1 continues on the next page
IB/M/Jun20/7405/2
CHEMISTRY
Paper 2 Organic and Physical Chemistry
Monday 8 June 2025 Afternoon Time allowed: 2 hours
Materials
For this paper you must have: For Examiner’s Use
• the Periodic Table/Data Booklet, provided as an insert (enclosed)
• a ruler with millimetre measurements Question Mark
• a scientific calculator, which you are expected to use where appropriate.
1
Instructions 2
• Use black ink or black ball-point pen.
• Fill in the boxes at the top of this page. 3
• Answer all questions.
4
• You must answer the questions in the spaces provided. Do not write outside the
box around each page or on blank pages. 5
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). 6
• All working must be shown.
7
• Do all rough work in this book. Cross through any work you do not want to be
marked. 8
9
Information
• The marks for questions are shown in brackets. TOTAL
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
• The maximum mark for this paper is 105.
, lOMoAR cPSD| 56342273
2
Do not write
outside the
box
*JUN207405201*
IB/M/Jun20/E11 7405/2
Answer all questions in the spaces provided.
This question is about rates of reaction.
0 1
Phosphinate ions (H2PO2–) react with hydroxide ions to produce hydrogen gas as
shown.
H2PO2– + OH− → HPO32– + H2
A student completed an experiment to determine the initial rate of this reaction. The
student used a solution containing phosphinate ions and measured the volume of
hydrogen gas collected every 20 seconds at a constant temperature. Figure 1
shows a graph of the student’s results.
Figure 1
IB/M/Jun20/7405/2
, lOMoAR cPSD| 56342273
3
Do not write
outside the
box
0 1
Use the graph in Figure 1 to determine the initial rate of reaction for this experiment.
.1
State its units. Show your working on the graph.
[3 marks]
Rate Units
*02*
Turn over ►
IB/M/Jun20/7405/2
, lOMoAR cPSD| 56342273
4
Do not write
outside the
box
Another student reacted different initial concentrations of phosphinate ions with an
0 1 .2 excess of hydroxide ions. The student measured the time (t) taken to collect 15
cm3 of hydrogen gas. Each experiment was carried out at the same temperature.
Table 1 shows the results.
Table 1
Initial [H2PO2–] / mol dm–3 t/s
0.25 64
0.35 32
0.50 16
1.00 4
State the relationship between the initial concentration of phosphinate and time (t).
Deduce the order of the reaction with respect to phosphinate.
[2 marks]
Relationship
Order
Question 1 continues on the next page
IB/M/Jun20/7405/2
