Acid is a chemical substance with a pH value ranging from 1 to 6 and bases are substances with 8 to 14 as pH values. Salts on the other hand are neutral and have a pH value of 7. pH value is the measure of the concentration of hydrogen ions in a substance and it can be measured using litmus papers. A base when it is dissolved in water forms an alkali solution. All of these have advantages and disadvantages like, acetic acid is present in vinegar, citric acid present in citrus fruits gives us Vitamin C, lactic acid is present in curd, ascorbic acid is present in Amla, calcium hydroxide occur in lime water and it is also the important component in cave formation, ammonium hydroxide is used in window cleaner, sodium hydroxide is used in soap. To test a solution and know its nature, one can use turmeric as it turns red when the solution is soap or basic. Even our blood has a pH value and it is basic as it has a high concentration of hydrogen ions. When an acid reacts with a base, it is an exothermic reaction that results in a base, water, and heat.