What is the chemical change happening to tobacco leaves when left exposed in the air?

Answer 1

When tobacco leaves are left exposed in the air, a chemical change known as oxidation occurs. This process involves the reaction of oxygen with various chemical compounds present in the tobacco leaves. Specifically, oxidation leads to the breakdown of complex organic molecules within the tobacco leaves, resulting in the formation of new compounds.

One important chemical change that occurs during oxidation is the conversion of nicotine, a major alkaloid found in tobacco, into various nicotine degradation products. These degradation products include cotinine, nornicotine, and anabasine, which are less potent and typically less addictive than nicotine itself.

Additionally, oxidation can cause changes in the flavor, aroma, and color of tobacco leaves. During this process, volatile compounds responsible for the characteristic scent of tobacco undergo chemical reactions, leading to the development of new odorous products. The breakdown of chlorophyll, the green pigment in plants, can also occur, resulting in the leaf changing color from green to brown.

Overall, the chemical changes that occur when tobacco leaves are left exposed in the air primarily involve the oxidation of organic compounds, leading to the breakdown of nicotine, alteration of flavor and aroma, and changes in color.