A Level Official Exam Material
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Unit 5: Transition Metals and
Organic Nitrogen Chemistry
Topic 17: Transition Metals and their Chemistry
For A Level students only
Q1. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Nickel is classified as a transition metal.
This is because nickel
A is a d block element
B has partially filled d orbitals
C forms stable ions with partially filled d orbitals
D forms stable compounds in which it has different oxidation states
(Total for question = 1 mark)
Q2. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Aqueous sodium hydroxide was added to aqueous iron(II) sulfate and the mixture allowed to stand.
What would be observed?
Q3. Which is not a bidentate ligand? (1)
A ethanedioate ion, C2O4 2–
B ethanoate ion, CH3COO–
C 1,2-diaminoethane, NH2CH2CH2NH2
D 2-aminoethanoic acid, NH2CH2COOH
(Total for question = 1 mark)
Q4. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Which of the following statements best explains carbon monoxide poisoning?
A carbon monoxide binds irreversibly to haemoglobin
B carbon monoxide forms stronger dative covalent bonds with haemoglobin than oxygen does
C the formation of carboxyhaemoglobin leads to a large increase in the entropy of the system
D carbon monoxide has a triple bond whereas oxygen has a double bond
(Total for question = 1 mark)
Q5. Which sketch shows the change in concentration of manganate(VII) ions with time in the reaction?
Q6. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Cobalt chloride is used as a test for the presence of water.
This test depends on the fact that
A anhydrous cobalt(II) chloride is blue and hydrated cobalt(II) chloride is pink
B anhydrous cobalt(II) chloride is pink and hydrated cobalt(II) chloride is blue
C cobalt(II) chloride is blue and cobalt(III) chloride is pink
D cobalt(II) chloride is pink and cobalt(III) chloride is blue
(Total for question = 1 mark)
Q7. This question is about complex ions.
(a) Which complex ion is square planar? (1)
A [Cu(H2O)2(NH3)4] 2+
B [CuCl4] 2–
C [Pt(NH3)2Cl2]
D [Ag(NH3)2] +
(b) Which copper complex ion is colourless? (1)
A [CuCl2] –
B [CuCl4] 2–
C [Cu(H2O)6] 2+
D [Cu(H2O)2(NH3)4] 2+
(c) Which complex ion includes a bond angle of 107°? (1)
A [Cr(NH3)6] 3+
B [CuCl2] –
C [CuCl4] 2–
D [Cr(H2O)6] 2+
(Total for question = 3 marks)
Q8. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross . Diamminecopper(I) ions are not coloured because:
A the d orbitals in copper(I) cannot be split
B the energy difference between the split d orbitals is outside the visible region of the spectrum
C d—d transitions are not possible because the d orbitals are fully occupied
D copper(I) complexes are readily oxidised
(Total for question = 1 mark)
Q9. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
A ligand must be an
A electron-pair donor
B electron-pair donor and negatively charged
C electron-pair acceptor
D electron-pair acceptor and negatively charged
(Total for question = 1 mark)
Q10. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
In acidic conditions, manganate(VII) ions are reduced to manganese(II) ions, Mn2+ .
In neutral conditions, manganate(VII) ions are reduced to manganese(IV) oxide, MnO2.
22.0 cm3 of a solution of manganate(VII) ions were needed to oxidise 25.0 cm3 of a solution of iron(II) ions to iron(III) ions in acidic conditions.
The same solution of manganate(VII) ions is used to oxidise 25.0 cm3 of the same solution of iron(II) ions in neutral conditions.
By considering the oxidation number changes involved, it may be shown that the volume of the manganate(VII) solution required, in neutral conditions, is A 12.6 cm3
B 13.2 cm3
C 36.7 cm3
D 38.5 cm3
(Total for question = 1 mark)
Q11. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Which of the following is not true of the reactions occurring in the catalytic converter fitted to a car exhaust?
A they involve heterogeneous catalysis
B carbon monoxide is adsorbed onto the surface of the catalyst
C nitrogen is desorbed from the surface of the catalyst
D the products cause no harm to the environment
(Total for question = 1 mark)
Q12. Answer the question with a cross in the box you think is correct . If you change your mind about an answer, put a line through the box and then mark your new answer with a cross . Iodide ions are oxidised by peroxodisulfate ions in aqueous solution.
This reaction is catalysed by adding Fe2+ ions to the solution.
This catalysis is effective because
A Fe2+ reacts with iodide ions and with peroxodisulfate ions
B Fe2+ has many electrons in its outermost subshell
C Fe2+ has many active sites on which the reaction can occur
D Fe2+ is readily oxidised to Fe3+ which is then reduced to Fe2+
(Total for question = 1 mark)
Q13. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Excess aqueous sodium thiosulfate is added to an aqueous solution of ammonium vanadate(V).
What colour is the mixture when the reaction is complete?
Refer to page 10 of the Data Booklet. (1)
A yellow
B blue
C green
D violet
Use this space for rough working.
Anything you write in this space will gain no credit.
(Total for question = 1 mark)
Q14. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Aqueous ammonia is added drop by drop to a solution of cobalt(II) chloride, CoCl2(aq), until in excess.
What would be the sequence of observations?
A blue solution → pink precipitate → dark blue solution
B pink solution → blue precipitate
C blue solution → pink precipitate
D pink solution → blue precipitate → yellow-brown solution
(Total for question = 1 mark)
Q15. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Which reagent, when added to aqueous sodium dichromate(VI), Na2Cr2O7(aq), causes a shift in equilibrium resulting in the formation of a yellow solution?
A NaOH(aq)
B HCl(aq)
C Zn(s)
D H2O2(aq)
(Total for question = 1 mark)
Q16. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross . Copper(II) ions form a complex with 1,2-diaminoethane (symbol 'en') with the formula Cu(en)3 2+ .
What type of ligand is 1,2-diaminoethane, and what is the coordination number of copper(II) in the complex?
Q17. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
Which of these has the greatest number of unpaired electrons in each of its atoms?
A chromium
B iron
C manganese
D vanadium
(Total for question = 1 mark)
Q18. Which vanadium ion is yellow in aqueous solution? (1)
A VO2+
B VO2 +
C V 3+
D V 2+
(Total for question = 1 mark)
Q19. For each question, select one answer from A to D and put a cross in the box .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
This question is about transition metal complexes.
(a) The bonding within the complex [Cu(NH3)4(H2O)2] 2+ is (1)
A covalent, dative covalent and ionic
B covalent and dative covalent only
C covalent only
D dative covalent only
(b) Which complex is tetrahedral? (1)
A [Pt(NH3)2Cl2]
B [Cu(H2O)4(OH)2]
C [Cu(NH3)4(H2O)2] 2+
D [CoCl4] 2−
(c) Which complex contains a bidentate ligand? (1)
A [Co(NH2CH2CH2NHCH2CH2NH2)2] 3+
B [Cu(NH3)4(H2O)2] 2+
C [Ni(NH2CH2CH2NH2)3] 2+
D [Mn(EDTA)]2−
(Total for question = 3 marks)
Q20. This question is about titanium(III) chloride, TiCl3.
(a) Titanium(III) chloride is used as a catalyst in the production of poly(propane).
State the property of transition metals, such as titanium, that makes their compounds effective catalysts. (1) ............................................................................................................................................. .............................................................................................................................................
(b) When dissolved in tetrahydrofuran (THF), titanium(III) chloride forms a blue solution containing complex Y.
(i) THF acts as a monodentate ligand in complex Y. State the meaning of the terms monodentate and ligand. (2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. .............................................................................................................................................
(ii) Complex Z is a stereoisomer of complex Y. Complete the diagram to show the arrangement of the ligands in complex Z. (1)
(c) A student determines the change in oxidation number of nitrogen when a solution of magnesium nitrate, Mg(NO3)2, is titrated with aqueous titanium(III) chloride.
Procedure Step 1 Using a volumetric flask, prepare 100.0 cm3 of an aqueous solution containing 0.750 g of solid Mg(NO3)2·6H2O.
Step 2 Pipette 10.0 cm3 of the solution from Step 1 into a conical flask and add a few drops of alizarin indicator.
Add 2 cm3 of concentrated hydrochloric acid and heat the mixture.
Step 3 Fill a burette with 0.0850 mol dm–3 aqueous titanium(III) chloride and titrate the contents of the conical flask from
Step 2 while continuing to heat the mixture.
During the titration, Ti3+ ions are oxidised to TiO2+ ions Ti3+ + H2O → TiO2+ + 2H+ + e – Alizarin indicator is green in the presence of aqueous Ti3+ and yellow in the presence of aqueous TiO2+ .
The end-point of the titration is reached on the addition of 20.70 cm3 of aqueous titanium(III) chloride. (i) State the colour change that would be observed at the end-point of the titration. (1)
From ........................................................... to ...........................................................
(ii) Use the results to determine the final oxidation state of nitrogen in the titration.
You must show your working.
[Mr value: Mg(NO3)2·6H2O = 256.3] (5)
(iii) Write the overall ionic equation for the titration reaction using your answer to (c)(ii) and the relevant half-equations from the list below. (2)
(iv) Use the electrode potential data provided to calculate for the overall titration reaction. (1)
(v) Suggest why the contents of the conical flask are heated. (1) ............................................................................................................................................. ............................................................................................................................................. .............................................................................................................................................
*(vi) The student's teacher said, "As TiCl3 is blue and TiO2+ions are colourless in aqueous solution, the titration can be carried out without an alizarin indicator."
Assess the teacher's statement.
In your answer you should
• identify, by name or formula, a coloured complex ion expected to be present when TiCl3 dissolves in water
• explain how the colour of this complex ion arises
• suggest why the titration may be more accurate with an alizarin indicator. (6)
(Total for question = 20 marks)
If you need the markscheme, including the examiners' reports for each question, and more exam and teaching materials on this topic, contact me through the contact page