Waec Model Questions Vol1 2021 Chemistry Question 9
Practice objective / multiple choice question 9 from the 2021 Waec Model Questions Vol1 Chemistry examination.
An industrial effluent containing phenol at a concentration of 30 mg L⁻¹ is discharged into a river. Phenol degrades in the river by first‑order biodegradation with a rate constant k = 0.15 day⁻¹. The permissible phenol concentration in the river is 2 mg L⁻¹. (a) Assuming no dilution, how many days will it take for the phenol concentration to fall to the permissible level? (b) If the river flow is 5.0×10⁵ L day⁻¹ and the effluent flow is 2.0×10⁴ L day⁻¹, what is the minimum dilution factor (river flow : effluent flow) required so that the phenol concentration after mixing is immediately at or below the permissible level (ignore degradation during mixing)?
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About This Question
This is Waec Model Questions Vol1 2021 Chemistry Question 9. It is a objective / multiple choice question from the 2021 Waec Model Questions Vol1 Chemistry examination.
Difficulty level: Hard .
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