Redox — Paper 2 · IGCSE Sciences - Co-ordinated (9-1) 0973

20 Three reaction equations are listed. 1 2Na + H2O → 2NaOH + H2 2 2NaCl → 2Na + Cl 2 3 CaCO3 → CaO + CO2 Which reactions involve reduction and oxidation? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

1 marks

Answer: A

This question in 0973/21 Oct/Nov 2019

19 The ionic equation for the formation of chromium(III) ions is shown. Cr  Cr3+ + 3e– Which statement about chromium atoms is correct? A They are oxidised by gaining electrons. B They are oxidised by losing electrons. C They are reduced by gaining electrons. D They are reduced by losing electrons.

1 marks

Answer: B

This question in 0973/21 May/June 2020

24 Chlorine gas is bubbled through two separate solutions. chlorine chlorine gas gas potassium bromide potassium iodide solution solution What is observed in the two tubes? potassium bromide tube potassium iodide tube A colourless solution turns orange colourless solution turns brown B colourless solution turns orange solution remains colourless C orange solution turns colourless brown solution turns colourless D orange solution turns colourless solution remains brown

1 marks

Answer: A

This question in 0973/21 May/June 2020

18 The ionic equation for the formation of chromium(III) ions is shown. Cr → Cr3+ + 3e– Which statement about chromium atoms is correct? A They are oxidised by gaining electrons. B They are oxidised by losing electrons. C They are reduced by gaining electrons. D They are reduced by losing electrons.

1 marks

Answer: B

This question in 0973/22 May/June 2020

19 Which word equation represents a redox reaction? A carbon + copper oxide  copper + carbon dioxide B hydrochloric acid + potassium hydroxide  potassium chloride + water C magnesium carbonate  magnesium oxide + carbon dioxide D sodium sulfate + barium nitrate  barium sulfate + sodium nitrate

1 marks

Answer: A

This question in 0973/21 Oct/Nov 2020

19 Which equation represents a redox reaction? A Ca(OH)2 + CO2  CaCO3 + H2O B CuCO3  CuO + CO2 C Mg + CuSO4  MgSO4 + Cu D Pb(NO3)2 + 2KI  PbI2 + 2KNO3

1 marks

Answer: C

This question in 0973/21 May/June 2021

19 Which changes show oxidation? 1 2Br –  Br2 2 Ca  Ca2+ 3 Fe3+  Fe2+ 4 O2  2O2– A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: A

This question in 0973/22 May/June 2021

18 Which equation represents a redox reaction? A CaCO3  CaO + CO2 B Cu(OH)2  CuO + H2O C LiOH + HCl  LiCl + H2O D 2Na + 2H2O  2NaOH + H2

1 marks

Answer: D

This question in 0973/21 Oct/Nov 2021

18 Sodium reacts with chlorine to form sodium chloride. The equation is shown. 2Na + Cl 2  2NaCl During the reaction, sodium atoms … 1 … electrons and chlorine molecules act as … 2 … . Which row completes gaps 1 and 2? 1 2 A gain an oxidising agent B gain a reducing agent C lose an oxidising agent D lose a reducing agent

1 marks

Answer: C

This question in 0973/21 May/June 2022

18 In which equation is the underlined substance reduced? A Cl 2 + 2KBr  2KCl + Br2 B 2Mg + O2  2MgO C 2PbO + C  CO2 + 2Pb D Zn + CuSO4  Cu + ZnSO4

1 marks

Answer: A

This question in 0973/22 May/June 2022

20 The equation for the reaction of iron(III) oxide and aluminium is shown. 2Al + Fe2O3  Al 2O3 + 2Fe Which statements about this reaction are correct? 1 Iron(III) ions are reduced. 2 O atoms gain electrons. 3 Fe2O3 is a reducing agent. 4 Al atoms lose electrons. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: B

This question in 0973/21 Oct/Nov 2022

20 The ionic equation for the reaction between iron(II) chloride and chlorine is shown. 2Fe2+ + Cl 2  2Fe3+ + 2Cl – Which row shows the substance that is reduced and the oxidising agent? substance oxidising reduced agent A Cl 2 Cl 2 B Cl 2 Fe2+ C Fe2+ Cl 2 D Fe2+ Fe2+

1 marks

Answer: A

This question in 0973/21 Oct/Nov 2023

19 In which equation is the underlined substance acting as an oxidising agent? A AgNO3 + NaCl  AgCl + NaNO3 B Cl 2 + 2KBr  Br2 + 2KCl C Fe2O3 + 3CO  2Fe + 3CO2 D H2 + PbO  Pb + H2O

1 marks

Answer: D

This question in 0973/22 May/June 2024

16 During electrolysis, reactions occur at the cathode and anode. Which statements about the electrode reactions are correct? 1 At the anode, anions gain electrons and are reduced. 2 At the anode, anions lose electrons and are oxidised. 3 At the cathode, cations gain electrons and are reduced. 4 At the cathode, cations lose electrons and are oxidised. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: C

This question in 0973/21 Oct/Nov 2025