Chemistry as level what does di substituted mean

These definitions are the preferred ones to be used in Organic Chemistry. Note that some terms (such as configuration) have more than one interpretation.

acid: an agent able to produce positively charged hydrogen ions (H+). [Since the hydrogen ion is a bare proton, it usually exists in a solvated form (such as H3O+).]

achiral: not chiral. A compound (or object) that is superimposible on its mirror image. For example CH4.

activation energy: the miminmum energy which reacting species must possess in order to be able to form an 'activated complex', or 'transition state', before proceeding to the products. [The activation energy (Ea) may be derived from the temperature dependence of the reaction rate using the Arrhenius equation.]

addition reactions: reactions in which an unsaturated system is saturated or part saturated by the addition of a molecule across the multiple bond.[E.g. the addition of bromine to ethene to form 1,2-dibromoethane]

alkaloid: organic substances occurring naturally, which are basic, forming salts with acids. The basic group is usually an amino function.

allyl group: a group containing 3 carbon atoms and a double bond [C1=C2-C3, where C3 is called the allyliuc position or allylic carbon atom].

allylic rearrangement: the migration of a double bond in a 3-carbon system from carbon atoms one and two to carbon atoms two and three,

the correct answer is:

a. formation of precipitation