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2001 Q28 (a) (3 marks)

 

(i) Define electrolysis. (1 mark)

 

(ii) Compare the reaction products from the electrolysis of molten sodium chloride and concentrated aqueous sodium chloride. (2 marks)

2002 - Q28 (e) (6 marks)

 

Evaluate changes in industrial production methods for sodium hydroxide.

2003 - Q30 (b) (4 marks)

 

During your practical work you performed a first-hand investigation to identify the products of electrolysis of sodium chloride.

 

(i) Describe ONE precaution you took to minimise hazards, or to dispose of reactants and products safely. (1 mark)

 

(ii) Outline the procedure you used to identify the products of electrolysis of sodium chloride. (3 marks)

2006 - Q28 (a) (5 marks)

 

During your practical work you performed a first-hand investigation to identify the products of electrolysis of sodium chloride.

 

(i)Outline a risk assessment for this investigation, and show how this would influence the experimental procedure. (3 marks)

 

(ii) Provide a conclusion based on one set of observations from your first-hand investigation. (2 marks)

2005 - Q28 (c) (7 marks)

 

Advances in chemistry have impacted on the development of technologies.

 

Discuss this statement by analysing changes that have occurred in industrial methods for the production of sodium hydroxide.

2007 - Q28 (b) (6 marks)

 

Over the past century the production of sodium hydroxide has evolved from the mercury process, to the diaphragm process, to the membrane process.

 

Analyse the factors that contributed to each of the changes in the production process.

2011 - Q33 (c) (5 marks)

 

A 0.05 mol L–1 solution of sodium chloride was electrolysed using graphite electrodes. Separate pieces of litmus paper were dipped into the solution next to each electrode.

 

The following observations were made.

 

            Polarity of electrode    Observation      Colour of litmus paper

                        Positive                Bubbles                           Red

                       Negative                Bubbles                          Blue

 

(i) Account for the observations at the anode and cathode. Include relevant chemical equations in your answer. (3 marks)

 

(ii) What is the difference between the electrolytic cell described above and a galvanic cell, in terms of energy requirements? (2 marks)

2013 - Q32 (d) (5 marks)

 

A first-hand investigation is conducted on the electrolysis of an aqueous solution of sodium chloride.

 

(i) Justify the use of a safety precaution, other than wearing safety glasses, when carrying out this investigation. (2 marks)

 

(ii) Describe how the THREE products of this electrolysis could be identified. (3 marks)

2015 - Q31 (d) (7 marks)

 

Compare the membrane cell method with ONE other method used in the industrial production of sodium hydroxide in terms of technical and environmental issues.

2008 - Q29 (b) (6 marks)

 

A first-hand investigation was performed to observe the electrolysis of sodium chloride.

 

(i) Describe an appropriate procedure. (3 marks)

 

(ii) Identify the reactions that occur at the anode and at the cathode and give equations for these reactions. (2 marks)

 

(iii) What condition would need to be changed to produce sodium metal as a product? (1 mark)

2010 - Q32 (a) (b) (8 marks)

 

(a) Identify the type of cell shown and outline the process used in the extraction of sodium hydroxide. (3 marks)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(b) Compare the electrolysis of molten sodium chloride and aqueous sodium chloride. Write the relevant half equations and overall reaction for each process. (5 marks)

2012 - Q34 (a) (3 marks)

 

The following equipment was set up and the reaction allowed to proceed. Gases were produced at both electrodes.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Name this process and identify the gas at each electrode.

2014 - Q32 (c) (5 marks)

 

Electrolysis is used in the industrial production of sodium hydroxide.

 

(i) Contrast the energy transformations in galvanic and electrolytic cells. (2 marks)

 

(ii) The table shows the products of three different electrolytic cells involving aqueous or molten sodium chloride.

 

                             Cell              Anode                    Cathode

                               X                  O2(g)                       H2(g)

                               Y                  Cl2(g)                       H2(g)

                               Z                  Cl2(g)                       Na(l)

 

Explain which of the three electrolytic cells from the table is used for the industrial production of sodium hydroxide. (3 marks)

2016 - Q31 (b) (7 marks)

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A first-hand investigation to electrolyse a solution of sodium chloride is to be performed.

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(i) Outline a procedure that is suitable for carrying out this investigation in a school laboratory. In your answer, address a safety issue. (3 marks)

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(ii) Describe how one of the products of the electrolysis of the sodium chloride solution can be identified. In your answer, refer to the chemistry occurring at each of the electrodes. (4 marks)

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