Separation of a carboxylic acid
Separation of a Carboxylic Acid from a Neutral Compound by Extraction
Reference: Smith, Chapter 2 (Acids and Bases)
Introduction
Carboxylic acids and phenols are two families of organic compounds that contain carbon, hydrogen and oxygen, and also react with water to yield an excess of hydronium ions over hydroxide ions. Pure water has a pH of 7, which means it has a hydronium ion concentration, [H3O+] of 10-7 M (M = molarity, moles/Liter). The hydronium ions in pure water come from the self-ionization of water. The self-ionization of water produces one hydronium ion and one hydroxide ion (OH-) for every two water molecules that react with each other. Therefore, every time a hydronium ion is made by the self-ionization of water, a hydroxide ion is also made. So, the concentration of hydronium ions always equals the concentration of hydroxide ions in pure water, because they are made by the same process the (self-ionization reaction). Thus, the concentration of hydroxide ions in pure water is also 10-7 M and the pOH is 7.
The number of hydronium ions and hydroxide ions is very small as compared to the number of un-ionized water molecules. Of every one billion water molecules, only two self-ionize. However, it is important to understand that pure water contains some hydronium ions and an equal number of hydroxide ions, even though the percentage of these ions is very small. What happens when we add an acid to water? Answer: It depends on whether the acid is a strong acid or a weak acid. A strong acid ionizes 100%, and a weak acid ionizes only slightly, perhaps 3-5%. Hydrochloric acid is a strong acid. When a HCl(g) molecule is dissolved in water, the covalent bond holding the H and Cl atoms together is broken. The hydrogen atom forms a new bond with an oxygen atom of water, making a hydronium ion. The chlorine atom keeps the two electrons of its bond with hydrogen, making a chloride ion. The process is shown in the equation below. All HCl molecules or
Reference: Smith, Chapter 2 (Acids and Bases)
Introduction
Carboxylic acids and phenols are two families of organic compounds that contain carbon, hydrogen and oxygen, and also react with water to yield an excess of hydronium ions over hydroxide ions. Pure water has a pH of 7, which means it has a hydronium ion concentration, [H3O+] of 10-7 M (M = molarity, moles/Liter). The hydronium ions in pure water come from the self-ionization of water. The self-ionization of water produces one hydronium ion and one hydroxide ion (OH-) for every two water molecules that react with each other. Therefore, every time a hydronium ion is made by the self-ionization of water, a hydroxide ion is also made. So, the concentration of hydronium ions always equals the concentration of hydroxide ions in pure water, because they are made by the same process the (self-ionization reaction). Thus, the concentration of hydroxide ions in pure water is also 10-7 M and the pOH is 7.
The number of hydronium ions and hydroxide ions is very small as compared to the number of un-ionized water molecules. Of every one billion water molecules, only two self-ionize. However, it is important to understand that pure water contains some hydronium ions and an equal number of hydroxide ions, even though the percentage of these ions is very small. What happens when we add an acid to water? Answer: It depends on whether the acid is a strong acid or a weak acid. A strong acid ionizes 100%, and a weak acid ionizes only slightly, perhaps 3-5%. Hydrochloric acid is a strong acid. When a HCl(g) molecule is dissolved in water, the covalent bond holding the H and Cl atoms together is broken. The hydrogen atom forms a new bond with an oxygen atom of water, making a hydronium ion. The chlorine atom keeps the two electrons of its bond with hydrogen, making a chloride ion. The process is shown in the equation below. All HCl molecules or