Neco Model Questions Vol1 2023 Chemistry Question 26
Practice objective / multiple choice question 26 from the 2023 Neco Model Questions Vol1 Chemistry examination.
A wastewater stream contains 120 mg L⁻¹ of pollutant X. It is treated in two successive stages. The first stage removes 40 % of X, and the second stage removes 30 % of the X remaining after the first stage. After the second stage, 10 % of the remaining X is converted into a more toxic by‑product Y (the conversion reduces the amount of X accordingly). The regulatory limits are: X ≤ 30 mg L⁻¹, Y ≤ 5 mg L⁻¹, and total oxygen demand ≤ 80 mg L⁻¹, where each mg of X consumes 1.5 mg O₂ and each mg of Y consumes 2.0 mg O₂. Does the treated effluent comply with all three limits? State which limit(s) are violated, if any.
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About This Question
This is Neco Model Questions Vol1 2023 Chemistry Question 26. It is one of the objective questions from the 2023 Neco Model Questions Vol1 Chemistry examination.
Difficulty level: Hard .
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