Tennessee Wastewater Operator Practice Exam

Which of the following substances is not considered corrosive?

1. Sulfuric acid

2. Hydrochloric acid

3. Carbon monoxide

4. Acetic acid

The correct answer is: Carbon monoxide

Corrosive substances are materials that can cause damage to living tissue or severe corrosion of materials upon contact. When evaluating the options provided, carbon monoxide is not classified as a corrosive substance. Carbon monoxide is a colorless, odorless gas produced by the incomplete combustion of carbon-containing fuels. Its primary concern is related to its toxicity and ability to interfere with the oxygen-carrying capacity of blood rather than any corrosive effects it may cause. It does not react aggressively with metals or organic tissues in the way acids and other corrosive materials do. In contrast, sulfuric acid, hydrochloric acid, and acetic acid are all classified as corrosive. Sulfuric acid and hydrochloric acid are strong acids that can cause severe damage to skin and materials upon contact. Acetic acid, while a weaker acid, can still cause corrosion to metals and irritation to skin and eyes upon exposure. Understanding the properties of these substances is critical for safe handling and regulation in wastewater treatment processes, where corrosivity can significantly impact equipment integrity and worker safety.