Igcse Model Questions Vol1 2018 Chemistry Question 24
Practice objective / multiple choice question 24 from the 2018 Igcse Model Questions Vol1 Chemistry examination.
A wastewater stream contains phenol at a concentration of 150 mg L⁻¹. First, a biological treatment removes 60 % of the phenol. The remaining phenol is then oxidised completely by potassium permanganate according to \(3\,\text{C}_6\text{H}_5\text{OH} + 2\,\text{KMnO}_4 \rightarrow 3\,\text{C}_6\text{H}_4\text{O}_2 + 2\,\text{MnO}_2 + 2\,\text{KOH} + 3\,\text{H}_2\text{O}\). (i) Calculate the mass of KMnO₄ (in mg L⁻¹) required for the oxidation of the phenol that remains after the biological stage. (ii) Determine the total theoretical oxygen demand (as mg L⁻¹ of O₂) for the complete oxidation of the phenol (both stages). Use molar masses: phenol 94.11 g mol⁻¹, KMnO₄ 158.04 g mol⁻¹, O₂ 32.00 g mol⁻¹.
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This is Igcse Model Questions Vol1 2018 Chemistry Question 24. It is one of the objective questions from the 2018 Igcse Model Questions Vol1 Chemistry examination.
Difficulty level: Hard .
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