Question

One of the following is an example of chemical method of evaluation

• A. Determination of volatile oil
• B. Determination of refractive index
• C. Detection of alkaloids
• D. Determination of vascular bundles

Answer 1

The Correct Option is C

The question asks us to identify an example of a chemical method of evaluation from the provided options. The correct answer is "Detection of alkaloids". Let's explore why this option is correct and why the others are not:

1. Determination of volatile oil: This is a physical method, commonly involving processes like steam distillation, where the volatile oils are separated based on their physical properties like boiling point. Thus, it is not a chemical method of evaluation.
2. Determination of refractive index: This is another physical method, which involves measuring how light is bent, or refracted, when it passes through a substance. This method does not involve any chemical reaction or change.
3. Detection of alkaloids: This is indeed a chemical method. Alkaloids are detected using chemical reactions with specific reagents like Dragendorff's reagent, Mayer's reagent, etc., which react with alkaloids to form colored precipitates. This is a definitive chemical method because it involves chemical analysis and identification.
4. Determination of vascular bundles: This is a morphological or anatomical analysis often determined using a microscope to observe the arrangement of vascular tissues in plant samples. It does not involve a chemical process.

The detection of alkaloids involves the use of chemical reagents that react specifically with the alkaloid compounds to form identifiable products, thus making it a chemical method. Therefore, the option "Detection of alkaloids" is the correct answer.