Derivative (finance) In finance, a derivative is a contract that derives its value from the performance of an underlying entity. This underlying entity can be an asset, index, or interest rate, and is often simply called the underlying.
Examples. Preservatives are either natural or chemical. Examples of chemical preservatives include nitrates, sulfites, sodium benzoate, potassium sorbate, and propyl gallate. Common natural preservatives include salt, lemon juice (citric acid), vinegar (acetic acid), sugar, and certain spices.unction. Preservatives work in one of three ways. They can prevent growth of microorganisms by creating an environment hostile to them. They can block the process of oxidation that causes foods to turn rancid.
Preservative-treated wood is wood which has been surface coated (non-pressure treated wood), where the application of preservative is by brushing, spraying or dipping the piece) or impregnated by means of pressure with chemicals (Pressure Treated Wood) which improve resistance to damage from decay and insect attack.