Neco Model Questions Vol1 2018 Chemistry Question 8

Practice objective / multiple choice question 8 from the 2018 Neco Model Questions Vol1 Chemistry examination.

Neco Model Questions Vol1 2018 Chemistry Objective / Multiple Choice Hard Difficulty
Question 8 NECO_MODEL_QUESTIONS_VOL1 • 2018 • CHEMISTRY • objective

A river with a flow rate of 200 m³ s\(^{-1}\) (phenol concentration negligible) receives a wastewater discharge of 5 m³ s\(^{-1}\) containing phenol at 500 mg L\(^{-1}\). After complete mixing, the phenol undergoes first‑order degradation with rate constant \(k = 0.1\ \text{day}^{-1}\). Calculate the phenol concentration (in µg L\(^{-1}\)) after the water has travelled for 2 days downstream, and state whether it complies with the WHO guideline limit of 10 µg L\(^{-1}\).

Answer Options

A. ≈5 000 µg L⁻¹; does not meet the WHO limit
B. ≈10 000 µg L⁻¹; meets the WHO limit
Correct Answer C. ≈10 000 µg L⁻¹; does not meet the WHO limit
D. ≈20 000 µg L⁻¹; does not meet the WHO limit
Correct Answer
C
Correct Option:
≈10 000 µg L⁻¹; does not meet the WHO limit

About This Question

This is Neco Model Questions Vol1 2018 Chemistry Question 8. It is one of the objective questions from the 2018 Neco Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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