Which of the following compounds would be least likely to undergo a gravimetric analysis?

Gravimetric analysis is a technique in analytical chemistry that relies on measuring the mass of a substance to determine its concentration or quantity within a sample. This method is most effective for stable, solid materials that can be isolated and accurately weighed.

Gases are least likely to undergo gravimetric analysis because they do not have a fixed shape or volume, making it challenging to capture and weigh them directly. When performing gravimetric analysis, the sample typically needs to be converted into a solid form that can be filtered, dried, and weighed. This is difficult with gases, as they can easily escape into the atmosphere and are often not conducive to being measured by mass directly.

In contrast, aqueous solutions, solids, and colloidal solutions can all be analyzed using gravimetric methods because they can be manipulated and isolated into a solid state suitable for accurate mass measurement. Aqueous solutions can often be precipitated, solids can be weighed directly, and colloidal solutions can be treated to yield solid phases that can be filtered and quantified.