Canadian Entry To Practice (CETP) Practice Test 2025 - Free CETP Practice Questions and Study Guide

The statement that Carbon Monoxide can be present without aldehydes being present is indeed true. Carbon Monoxide (CO) is a colorless, odorless gas produced from the incomplete combustion of carbon-containing materials. It can be found in various environments, such as urban areas with vehicle emissions, poorly ventilated spaces with gas appliances, and even in smoke from fires, all without the presence of aldehydes.

Aldehydes, on the other hand, are a different group of compounds that can also be produced by incomplete combustion, but their formation is not directly linked to the presence of Carbon Monoxide. Therefore, it's entirely possible to have CO in the atmosphere without accompanying aldehyde compounds. This differentiation is key in understanding the presence of various pollutants and their sources in environmental contexts.

The other options imply conditions or relationships that do not universally apply; CO can exist independently from aldehydes without restrictions on concentration levels.