Why is grass ground with ethanol?

• A. Grass is ground with ethanol rather than water because chlorophyll is more soluble in ethanol.
• B. Grass is ground with water because ethanol destroys chlorophyll.
• C. Grass is ground with ethanol to dissolve sugars.
• D. Grass is ground with solvent that smells better.

Answer: (A)

The main idea is why a solvent is chosen to extract plant pigments. Chlorophyll dissolves much better in ethanol than in water because it is largely non-polar due to its long phytol tail, so an organic solvent like ethanol can dissolve and carry the pigment out of the leaf tissues more effectively. Water, being very polar, doesn’t dissolve chlorophyll well, so grinding grass in water wouldn’t extract as much pigment. The other ideas aren’t the reason: ethanol isn’t used to destroy chlorophyll in this context, sugars are more soluble in water, and the smell of the solvent isn’t a scientific justification.