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1 markOxidation – Reduction Reactions

CSEC Chemistry · January 2016 · Paper 2 · Question 2(a)

Sodium hypochlorite (NaClO) is an oxidizing agent in chlorine bleach. It forms hypochlorous acid (HOCl) in water: NaClO + H₂O → HOCl + NaOH (Equation 1). Hypochlorite and chlorine are in equilibrium in water, with low pH favoring chlorine: Cl₂ + H₂O ⇌ H⁺ + Cl⁻ + HOCl (Equation 2).

State ONE use of bleach in the laundering of clothing.

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Other parts of this question

  1. 2(b)(i)Define, in terms of oxidation state, the term 'oxidizing agent'.[1 mark]
  2. 2(b)(ii)Define, in terms of oxidation state, the term 'oxidation'.[1 mark]
  3. 2(c)Deduce the oxidation number of Cl in the formula, NaClO.[3 marks]
  4. 2(d)(i)What is the change in oxidation number of Cl for the process?[2 marks]
  5. 2(d)(ii)Is this an oxidation or reduction process?[1 mark]
  6. 2(d)(iii)Describe a simple laboratory test for chlorine gas.[2 marks]
  7. 2(e)During one stage of the reaction, H₂O₂(aq) is converted to H₂O(l). Use the changes in oxidation number to determine whether this is an oxidation or reduction…[4 marks]

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