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2 marksWater

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

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.

Describe a qualitative chemical test that can be used in school laboratories to detect the presence of aqueous nitrate ions.

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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)(ii)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…[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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