Neco 2019 Chemistry Question 50

Practice objective / multiple choice question 50 from the 2019 Neco Chemistry examination.

Neco 2019 Chemistry Objective / Multiple Choice Hard Difficulty

Question 50 NECO • 2019 • CHEMISTRY • objective

A wastewater stream contains phenol at a concentration of 150 mg/L. It undergoes a two‑stage treatment: the first biological stage removes 60 % of the phenol, and the second advanced oxidation stage removes 80 % of the phenol remaining after the first stage. The treated effluent is then mixed with river water at a ratio of 1 : 4 (treated : river). The river water initially contains phenol at 10 mg/L. Determine the phenol concentration in the river after mixing and state whether it complies with the permissible limit of 5 mg/L.

Correct Answer A. 10.4 mg/L, does not comply

B. 8.2 mg\/L, does not comply

C. 12.0 mg\/L, does not comply

D. 5.0 mg\/L, complies

Correct Answer

Correct Option:

10.4 mg/L, does not comply

This is Neco 2019 Chemistry Question 50. It is one of the objective questions from the 2019 Neco Chemistry examination.

Difficulty level: Hard .

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