Waec Model Questions Vol1 2025 Chemistry Question 8

Practice objective / multiple choice question 8 from the 2025 Waec Model Questions Vol1 Chemistry examination.

Waec Model Questions Vol1 2025 Chemistry Objective / Multiple Choice Hard Difficulty

Question 8 WAEC_MODEL_QUESTIONS_VOL1 • 2025 • CHEMISTRY • objective

A factory discharges effluent at 200 L·min⁻¹ containing 0.05 mol·L⁻¹ phenol. The river flow is 5000 L·min⁻¹ and phenol degrades in the river by first‑order kinetics with k = 0.03 min⁻¹. Assuming instantaneous mixing, what is the phenol concentration (mol·L⁻¹) 30 minutes downstream?

Answer Options

A. 6.5×10⁻⁴ mol·L⁻¹

B. 1.2×10⁻³ mol·L⁻¹

Correct Answer C. 7.8×10⁻⁴ mol·L⁻¹

D. 3.9×10⁻⁴ mol·L⁻¹

Correct Answer

Correct Option:

7.8×10⁻⁴ mol·L⁻¹

About This Question

This is Waec Model Questions Vol1 2025 Chemistry Question 8. It is a objective / multiple choice question from the 2025 Waec Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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