Question

1,write an equation to describe the method of converting a water insoluble organic acid in to a eater soluble salt?

2, during the process of using a separatory funnel an enulsionis occasionally formed, how may the emulsion be broken?

Answer 1

1)

In general, the most acidic organic compounds are the carboxylic acids, RCO₂H . The vast majority of carboxylic acids are soluble in organic solvents and insoluble in water. In contrast, the conjugate bases of carboxylic acids (carboxylate ions) are usually water-soluble. Thus, by reacting a water-insoluble carboxylic acid with an appropriate base, it can be converted into a water-soluble salt

Because of their enhanced acidity, carboxylic acids react with bases to form ionic salts, as shown in the following equations. In the case of alkali metal hydroxides and simple amines (or ammonia) the resulting salts have pronounced ionic character and are usually soluble in water. Heavy metals such as silver, mercury and lead form salts having more covalent character (3rd example), and the water solubility is reduced, especially for acids composed of four or more carbon atoms.

RCO2H	+	NaHCO3		RCO2(–) Na(+) + CO2 + H2O
RCO2H	+	(CH3)3N:		RCO2(–) (CH3)3NH(+)
RCO2H	+	AgOH		RCO2δ(-) Agδ(+) + H2O

2)

IMAGE .A mixture that has formed an emulsion. The emulsion is the opaque area (grayish) near the middle of the image.

Occasionally, emulsions can form while the liquids are being mixed in the separatory funnel. An emulsion occurs when small droplets of an organic solvent are suspended in a water solution. Emulsions can be difficult to disperse, however, a few techniques may be attempted.

If the solutions that will be mixed in the funnel are known to emulsify, be prepared to wait for the emulsion to break down or consider using one of the techniques described below to eliminate the emulsion.

Once an emulsion has formed, first try slowly and gently swirling the solution in the separatory funnel.

If the emulsion does not disperse after swirling or waiting, adding a small amount of saturated aqueous sodium chloride or water soluble detergent solution to the liquid in the separatory funnel will sometimes help. However, consider the reactivity of any reagent present in the separatory funnel before adding the salt.