Neco Model Questions Vol1 2017 Chemistry Question 18

Practice objective / multiple choice question 18 from the 2017 Neco Model Questions Vol1 Chemistry examination.

Neco Model Questions Vol1 2017 Chemistry Objective / Multiple Choice Hard Difficulty
Question 18 NECO_MODEL_QUESTIONS_VOL1 • 2017 • CHEMISTRY • objective

A steel pipe with an internal surface area of \(1500 \text{ cm}^2\) is immersed in seawater. The corrosion current density measured on the pipe surface is \(2.5 \;\mu\text{A cm}^{-2}\). The density of iron is \(7.87 \text{ g cm}^{-3}\) and its molar mass is \(55.85 \text{ g mol}^{-1}\). (a) Calculate the corrosion rate in millimetres per year. (b) If a protective coating reduces the corrosion current density by 80 %, what is the new corrosion rate (mm yr\(^{-1}\))? (c) Determine the mass of iron lost per year under the original (uncoated) condition, in kilograms.

Answer Options

A. a) 0.058 mm yr⁻¹; b) 0.0058 mm yr⁻¹ after coating; c) 0.068 kg of iron lost per year.
Correct Answer B. a) 0.029 mm yr⁻¹; b) 0.0058 mm yr⁻¹ after coating; c) 0.034 kg of iron lost per year.
C. a) 0.0029 mm yr⁻¹; b) 0.00058 mm yr⁻¹ after coating; c) 0.0034 kg of iron lost per year.
D. a) 0.029 mm yr⁻¹; b) 0.0116 mm yr⁻¹ after coating; c) 0.034 kg of iron lost per year.
Correct Answer
B
Correct Option:
a) 0.029 mm yr⁻¹; b) 0.0058 mm yr⁻¹ after coating; c) 0.034 kg of iron lost per year.

About This Question

This is Neco Model Questions Vol1 2017 Chemistry Question 18. It is one of the objective questions from the 2017 Neco Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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