Biological pigments answers
1. (a) In both acidic and alkaline solution cyanidin contains extensive conjugation. The delocalised pi electrons absorbs energy in the visible region of the spectrum as they are excited (to an empty orbital of higher energy, which is usually a non-bonding orbital) and the colour observed is the transmitted complementary colour. (b) There is greater conjugation in the structure of cyanidin in the alkaline solution (due...