What is the primary use of an Orsat Apparatus?

The Orsat Apparatus is primarily used to analyze flue gas concentrations. This device is designed to measure the specific components of flue gas, such as carbon dioxide (CO2), oxygen (O2), and carbon monoxide (CO). It works on the principle of gas absorption, where each gas is absorbed by a different liquid reagent and the volume of gas absorbed is measured. This information is crucial for assessing the efficiency of combustion processes and monitoring emissions from boilers, furnaces, and other combustion equipment. By accurately determining these concentrations, engineers can optimize fuel usage and reduce environmental impacts.

The other options do not align with the primary functions of the Orsat Apparatus. For instance, measuring smoke density or determining the OH levels in water involves different methodologies and instruments altogether. Temperature measurements in combustion processes also require specific thermometric devices rather than an Orsat Apparatus, which focuses specifically on gas compositions.