Question

Why are comparisons of particle sizes between different instrumental techniques only qualitative?

Short answer

Because some instrumental procedures require unique parameters, such as refractive index or density, the comparison of particle size between different instrumental approaches is qualitative. However, occasionally this type of information is unavailable, and in this instance, assumptions are made, resulting in inconsistencies.

Step-by-step solution

Concept Introduction

• Different instrumental procedures are used to determine particle size, and each instrumental technique requires different information.
• Some instrumental techniques require specific data, such as refractive index or density, and the availability of these data is not always guaranteed; as a result, leading to variations in results.

Explanation

• The comparison of the particle size of the instrument employed for the various procedures is always regarded as quantitative.
• Special qualities, like as refractive index or density, are required in various instrumental procedures.
• These forms of data are only useful for a few approaches, such as light scattering methods that require the refractive index, and sedimentation methods that require density.
• Because information is not always readily available, assumptions are made at times, resulting in differences.
• As a result, comparing particle size between various instrumental approaches is always qualitative.

Final answer

As some of the unique parameters such as refractive index or density are not always available, they are assumed as they are required for calculations in some of the instrumental procedures, which may result in inconsistencies. Hence, the comparison is only qualitative.