An acid is a species that is a proton donor and the word acid comes from the Latin word 'acidus' meaning sour. When an acid is added to water, it will give a solution with a pH of less than 7, pH is a measure of concentration of hydrogen ions in a solution. Most chemistry laboratories will have common strong acids, such as sulfuric acid (H2SO4), hydrochloric acid (HCl) and nitric acid (HNO3). Strong acids are acids that fully dissociates, and this means that it will be fully ionised in solution. Weak acids, that you are likely to come across everyday, includes ethanoic (acetic) acid which is in vinegar, methanoic (formic) acid which is in insect bites, and citric acid which is in citrus fruits). Weak acids are acids that partially dissociates and this means that it will only be partially ionised in solution.
All acids contain hydrogen and when an acid is added to water, the acid release H+ ions, also known as protons, into solution and as this happens with all acids, acids are known as proton donors. The H+ ion in an acid is the active ingredient and it is responsible for all reactions.
For example, HCl + solution (aq) ? H+ + Cl-
Bases are species that is a proton acceptor and reacts with acids to form salt and water. A salt is any chemical compound formed when a H+ from an acid has been replaced by a metal ion or any other positive ion. Positively charged ions, such as NH4+ are known as cations and anions are negatively charged ions which derives from an acid in a salt. For example , hydrochloric acid goes to chloride salts, such as sodium chloride.
A diprotic acid is an example of an acid that has two replaceable H+ ion and an example would be sulfuric acid. So if one proton from the acid is replaced then an acid salt is formed. For example H2SO4 goes to Na2SO4.
Salts can be formed from carbonates, bases and alkalis. An alkali is a type of base that dissolves in water forming hydroxide ions, OH- ions. Sodium hydroxide (NaOH), potassium hydroxide (KOH) and ammonia (NH3) are examples of alkalis When an acid reacts with a carbonate it produces a salt, carbon dioxide and water. When an acid reacts with a alkali or a base it produces a salt and water. Salts can also be formed from the reaction of reactive metals with acid in a reactions known as a redox (reduction and oxidation) reaction. When a salt is to be formed from the reaction of metals with acid a redox reaction takes place and this is when both reduction and oxidation take place. Oxidation is the loss of electrons and reduction is the gain of electrons. The metal from the reaction is oxidised, forming positive metal ions and the hydrogen in the acid is reduced. So if one species decreases its oxidation number, another species increases its oxidation number.
All acids contain hydrogen and when an acid is added to water, the acid release H+ ions, also known as protons, into solution and as this happens with all acids, acids are known as proton donors. The H+ ion in an acid is the active ingredient and it is responsible for all reactions.
For example, HCl + solution (aq) ? H+ + Cl-
Bases are species that is a proton acceptor and reacts with acids to form salt and water. A salt is any chemical compound formed when a H+ from an acid has been replaced by a metal ion or any other positive ion. Positively charged ions, such as NH4+ are known as cations and anions are negatively charged ions which derives from an acid in a salt. For example , hydrochloric acid goes to chloride salts, such as sodium chloride.
A diprotic acid is an example of an acid that has two replaceable H+ ion and an example would be sulfuric acid. So if one proton from the acid is replaced then an acid salt is formed. For example H2SO4 goes to Na2SO4.
Salts can be formed from carbonates, bases and alkalis. An alkali is a type of base that dissolves in water forming hydroxide ions, OH- ions. Sodium hydroxide (NaOH), potassium hydroxide (KOH) and ammonia (NH3) are examples of alkalis When an acid reacts with a carbonate it produces a salt, carbon dioxide and water. When an acid reacts with a alkali or a base it produces a salt and water. Salts can also be formed from the reaction of reactive metals with acid in a reactions known as a redox (reduction and oxidation) reaction. When a salt is to be formed from the reaction of metals with acid a redox reaction takes place and this is when both reduction and oxidation take place. Oxidation is the loss of electrons and reduction is the gain of electrons. The metal from the reaction is oxidised, forming positive metal ions and the hydrogen in the acid is reduced. So if one species decreases its oxidation number, another species increases its oxidation number.
