Substances are generally classified as acids, bases and neutral. To determine whether a substance is acidic, basic, or neutral, we can generally make use of indicators. If a substance is acidic, then it would turn blue litmus red. On the other hand, if a substance is basic, it would turn red litmus blue. Neutral substances will not have any effect on litmus paper. If a substance is acidic, then it would turn methyl orange paper red. If a substance is basic, it would turn methyl orange paper yellow. Acids generally have a sour taste whereas bases will have a bitter taste.
An acid is a substance that produces hydrogen ions in the solution. On the other hand, a base is a substance that produces hydroxyl ions in the solution. Depending on the number of protons, the acids are classified into monoprotic, diprotic, and triprotic. Hydrochloric acid (HCl) and Nitric acid (HNO3) are examples of monoprotic acid.Sulphuric acid (H2SO4) is an example of diprotic acid. Phosphoric acid (H3PO4) is an example of triprotic acid. Some of the typical examples of bases include NaOH, LiOH, and Mg(OH)2.
An acid readily undergoes a chemical reaction with active metals to form salt and hydrogen gas.
Metal Acid Salt Hydrogen gas
Zn (s) + 2HCl (aq) ———- ZnCl2 (aq) + H2 (g)
Mg (s) + 2HNO3 (aq) —— Mg(NO3)2 (aq)+ H2 (g)
An acid will also readily react with carbonate to form salt, water, and carbon dioxide gas.
Acid Carbonate Salt water Carbon dioxide
2HCl (aq) + Na2CO3 (aq)—–2NaCl (aq) + H2O + CO2
H2SO4 (aq) + MgCO3 (aq)—–MgSO4 (aq) + H2O + CO2 (g)
An acid would react with a base to form salt and water. This is termed as neutralization reaction
Acid Base Salt water
HCl (aq) + NaOH (aq)—– NaCl (aq) + H2O
H2SO4 (aq) + Ca(OH)2 (aq) —- CaSO4 (aq) + 2H2O
HNO3 (aq) + KOH (aq) ——— KNO3 (aq) + H2O
There are different kinds of products formed from acids and bases. This is because the reactions depend on the strength of acids and bases. The products formed from the reaction of strong acid with a weak base would differ from that formed when a weak acid reacts with a weak base. This could be attributed to the reactivity of acids. Strong acids would lead to the production of higher number of hydronium ions. On the other hand, weak acids would lead to the production of lesser number of hydronium ions.
Compared to acids, bases are much less reactive. One of the typical examples of bases includes saponification reaction. In this case, bases would react with organic acids to form soap.Animal fat or vegetable oil contain large chain fatty acids. These fatty acids would react with strong alkali such as NaOH or KOH to form soap and glycerin. Although water is present in the chemical reaction, it would not participate in the chemical reaction. A base would decrease the concentration of hydrogen ions when it reacts with water. When a strong base is used, it would decrease the concentration of hydrogen ions. At the same time, it would increase the concentration of hydroxide ions in the solution.