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2 marksWater

CAPE Chemistry Unit 2 · May/June 2025 · Paper 2 · Question 3(e)(ii)

Nitrates and phosphates are common pollutants in water. The cadmium reduction method is a standard method used in the determination of nitrates in industrial laboratories.

Compared to the cadmium reduction method, state, with reason, whether the method suggested in (e)(i) is suitable for the determination of nitrate ions as a pollutant in water samples.

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  1. 3(a)List FOUR factors that must be considered with respect to the location of an industrial plant.[2 marks]
  2. 3(b)(i)With the aid of equations, outline the first TWO steps in the Contact process.[5 marks]
  3. 3(b)(ii)Give an example of the use of an oxide of sulfur in the food industry.[1 mark]
  4. 3(b)(iii)State TWO environmental concerns associated with sulfur dioxide.[2 marks]
  5. 3(c)(i)With the aid of balanced equations, briefly explain how aluminium oxide is separated from bauxite ore.[7 marks]
  6. 3(c)(ii)Aluminium oxide is electrolysed to obtain aluminium (smelting). Write the main reactions occurring at the anode and cathode.[4 marks]
  7. 3(c)(iii)Describe any ONE impact of the production of alumina on the environment.[2 marks]
  8. 3(d)Write the equations that show the formation of these oxides.[2 marks]
  9. 3(e)(i)Describe a qualitative chemical test that can be used in school laboratories to detect the presence of aqueous nitrate ions.[2 marks]
  10. 3(e)(iii)Name the reagent that can be used in school laboratories to detect the presence of phosphate ions.[1 mark]

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