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ABA, a plant hormone is a carboxylic acid ABA, a plant hormone is a carboxylic acid The bright reds and purples we see in leaves are made mostly in the fall.The fruits of many plants are ripen and ready to harvest in this season.Abscisic acid (ABA), a plant hormone with carboxylic acid functional group is one of the reasons fordetachment of ripen leaves and fruits form the plants. ABA, also known as abscisin II and dormin,is a plant hormone. The name “abscisic acid’ was given because it was found in high concentrations innewly abscissed or freshly fallen leaves. The main function of ABA in plants is regulation of plant responsesto environmental stress and plant pathogens. Seed germination is inhibited by ABA in antagonism with gibberellin,another plant hormone. It also prevents loss of seed dormancy.

Learning Objectives

After completing the topic, the student will be able to:

  • Define carboxylic acids and list the carboxylic acid derivatives.
  • Describe the structure of carboxylic acid functional group.
  • Give the structural features of carboxylic acid derivatives.
  • Examine the effect of electronic displacements on acidity of carboxylic acids.
  • Examine the effect of substitute on reactivity of carboxylic acids.
  • Give the preparation methods, properties and uses of carboxylic acids.
  • Give the preparation methods, properties and uses of carboxylic acid derivatives.
  • Discuss the chemical composition and preparation methods of soaps.
  • Discuss the chemical composition and preparation methods of detergents.
  • Explain the cleansing action of soaps and detergents.
Carboxylic Acids Sources of Carboxylic acids Carboxylic acids are responsible for the sourness of lemons and vinegar and the discomfort that follows an ant bite.
Carboxylic Acids

Carboxylic acids are a family of organic chemicals containing the carboxyl group, ‐COOH. This is a complex functional group made up of a hydroxyl group, ‐OH (like the alcohols) and a carbonyl group, C=O (like the aldehydes and ketones). These two groups are joined together in the carboxyl group so that they have a distinct effect on each others chemistry and the reactions of the carboxylic acids tend to differ from those of corresponding alcohols, aldehydes and ketones.

The general formula of the mono‐carboxylic acids is RCOOH, where R may be a hydrogen atom, an alkyl group or an aryl group.

An ant, goat, rancid butter, bananas, silk and the epoxy resin glue are some of the things that are related to carboxylic acids and their derivatives.

Tracker dogs Tracker dogs Tracker dogs, given a scent of a person's clothing and thus their carboxylic acid mixture (mainly butanoic acid), can then recognize and follow that scent to track the individual concerned.
Examples of carboxylic acids

Ant bite sting because of the formic acid released by ants. Acetylsalicylic acid, the chemical name for aspirin, is an important analgesic (pain killer). Aspirin is an effective pain reliever and anti‐inflammatory drug to help us combat headaches, colds, flu, backache, toothache, etc.,

The significant odor of goats is due to caproic acid (hexanoic acid) and that of rancid butter is because of butanoic acid.

The green apples are sour due to the presence of malic acid. It is also present in grapes and in most wines. In the grape wine, malic acid is involved in many processes which are essential for the health and sustainability of the wine.

Silk is the result of polymerization of carboxylic acid derivatives called amino acids into proteins. The smell of bananas is due to the chemical ‐ isoamyl acetate, an ester (carboxylic acid derivative).