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Atoms and reactions

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Question 126

Hydrogen peroxide, H2O2\text{H}_2\text{O}_2H2​O2​, can be oxidised by manganate(VII) ions under acidic conditions as shown below:

2MnO4−(aq)+5H2O2(aq)+6H+(aq)⟶2Mn2+(aq)+5O2(g)+8H2O(l) 2\text{MnO}_4^-(\text{aq}) + 5\text{H}_2\text{O}_2(\text{aq}) + 6\text{H}^+(\text{aq}) \longrightarrow 2\text{Mn}^{2+}(\text{aq}) + 5\text{O}_2(\text{g}) + 8\text{H}_2\text{O}(\text{l}) 2MnO4−​(aq)+5H2​O2​(aq)+6H+(aq)⟶2Mn2+(aq)+5O2​(g)+8H2​O(l)

In a titration, 25.00 cm3 of a disinfectant containing hydrogen peroxide reacts completely with 20.00 cm3 of 0.160 mol dm-3 KMnO4(aq)\text{KMnO}_4(\text{aq})KMnO4​(aq). What is the concentration of H2O2\text{H}_2\text{O}_2H2​O2​, in mol dm−3\text{mol dm}^{-3}mol dm−3, in the disinfectant? Assume that KMnO4\text{KMnO}_4KMnO4​ only reacts with H2O2\text{H}_2\text{O}_2H2​O2​ in the disinfectant.

A

0.05120.05120.0512

B

0.1280.1280.128

C

0.3200.3200.320

D

0.4000.4000.400

Markscheme

Atoms and reactions Questions

  1. A Level
  2. /Chemistry
  3. /Atoms and reactions

199 exam-style questions on OCR A A Level Chemistry Atoms and reactions, covering Atomic structure and isotopes, Compounds, formulae and equations, Amount of substance, Acids, and Redox. Each one has a worked solution and a mark scheme showing where the marks go.

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