Waec Model Questions Vol1 2023 Chemistry Question 26

Practice objective / multiple choice question 26 from the 2023 Waec Model Questions Vol1 Chemistry examination.

Waec Model Questions Vol1 2023 Chemistry Objective / Multiple Choice Hard Difficulty
Question 26 WAEC_MODEL_QUESTIONS_VOL1 • 2023 • CHEMISTRY • objective

A municipal wastewater contains 40 mg L⁻¹ NH₃‑N and 20 mg L⁻¹ NO₂‑N. It is treated in two successive nitrification reactors. In the first reactor, 60 % of the NH₃‑N is oxidised to NO₂‑N and 30 % of the NO₂‑N present is further oxidised to NO₃‑N. In the second reactor, the remaining NH₃‑N is oxidised to NO₂‑N with 80 % efficiency, and the total NO₂‑N (including that formed in the first reactor) is oxidised to NO₃‑N with 70 % efficiency. No denitrification occurs. Determine the final concentrations (in mg L⁻¹) of NH₃‑N, NO₂‑N and NO₃‑N in the effluent.

Answer Options

A. NH₃‑N = 4.8 mg/L, NO₂‑N = 22.6 mg/L, NO₃‑N = 32.6 mg/L
Correct Answer B. NH₃‑N = 3.2 mg/L, NO₂‑N = 24.2 mg/L, NO₃‑N = 32.6 mg/L
C. NH₃‑N = 4 mg/L, NO₂‑N = 26.2 mg/L, NO₃‑N = 29.8 mg/L
D. NH₃‑N = 3.2 mg/L, NO₂‑N = 15.2 mg/L, NO₃‑N = 41.6 mg/L
Correct Answer
B
Correct Option:
NH₃‑N = 3.2 mg/L, NO₂‑N = 24.2 mg/L, NO₃‑N = 32.6 mg/L

About This Question

This is Waec Model Questions Vol1 2023 Chemistry Question 26. It is one of the objective questions from the 2023 Waec Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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