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 one of the objective questions from the 2025 Waec Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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